MagnoliaThe Journal of the Magnolia Society International

Volume 47 Issue No. 92Fall /Winter 2012

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Magnolia sprengeri in ChinaErland Ejder, Swedish magnolia group

Nobody who has seen a flowering Magnolia sprengeri ‘Diva’ can help but be very impressed. The color, size and elegance of the flowers are supplemented by attractive leaves of special character and a strong tree habit. I first saw this remarkable plant in the magnolia garden of Karl Flinck many years ago and was, indeed, duly impressed. But to add to the physical attractions of this beauty is a century-old story of mystique about origin and taxonomic position. I am certainly not the only one to have been fascinated by this story – a very good and inspired article about it was published by the late Phil Savage, Jr. in this journal (Savage 1969). Also Neil Treseder (Treseder 1978) and Jim Gardiner (Gardiner 2000) have given ample attention to it in their magnolia books.

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For the real Magnolia aficionado, it is never enough to gaze admiringly at a beautiful plant and gradually I searched out all possible information about this new favorite.

HistoryThe basic facts are that Magnolia sprengeri ‘Diva’originates from seed lot #688 collected in the Changyang district of Hubei province, China, just after 1901 by Ernest H. Wilson, for Messrs. James Veitch. The seedling was raised by the Veitch company at their Coombe Wood nursery near Lon-don and sold at the going-out-of-business auction in 1913, having been bought by Charles Williams of Caerhays Castle, Cornwall, UK. It flow-ered with a pink bloom at Caerhays for the first time in 1919, and the value and importance of this plant was soon realized, in particular as the other plants from #688 turned out to have white flowers.

The interest in M. sprengeri is multi-faceted. The knowledge of the distri-bution has been very scant, in particular the possibly different habitats of the red-pink and the white varieties. The idea that the cultivar ‘Diva’ might be a single chance hybrid has been aired. The taxonomy has been uncertain, one problem being the unknown color of the type specimen flowers, and the degree of variation in morphological characters has been. a mystery. There are around twenty registered hybrids where M. sprengeri 'Diva' is assumed to be either the seed or pollen parent. However, very few of these can be traced back to the 'Diva' clone itself. What has been used is almost always 'Diva'-like open pollinated seedlings, first or second gen-eration. This was definitely the case with the hybrids containing what was thought to be 'Diva' in Phil Savage’s important pioneering work. Geneti-cally, it is of importance to be aware of their status because with selected forms of M. sprengeri that are superior in flower characteristics or hardi-ness, the value of this species in hybridization programs would be even higher.

Field investigationsAfter much deliberation, I contacted Professor Kang Yongxiang of the Northwest Agriculture and Forestry University in Yangling, just west of Xian in Shaanxi province of China, with whom I had dendrological contacts long before. Together we planned the exploration of magnolias in central China - M. sprengeri most importantly, but also M. biondii as a secondary interest, and whatever else might come our way. The Swedish Agricultural University sponsored a visit for Kang Yongxiang to Sweden for discussions and planning and Karl Flinck offered financial support for the Chinese participants who would be involved in the field work.

Wilson wrote about his observations 1900-1910, “In the parts of China I have travelled Magnolias are nowhere really common plants. Locally, here and there, individuals are fairly plentiful but numerically they constitute

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but an infinitesimal percentage of the forest flora.” (Wilson 1980) . He also often mentions the extreme difficulties of travelling in the mountain ar-eas of China: always slow, often dangerous and, during flowering time in spring, almost impossible along the muddy roads. Now, a hundred years later, the large-scale logging has crept ever higher up in the mountain wilderness with very severe consequences for the natural flora. On the other hand, the transportation situation has improved dramatically and movement is fast between and within the different provinces, whereas in the not-too-distant past, one would have to traverse crude and difficult mountain roads and trails. Other keys to our successful tours have been the most excellent relations Professor Kang Yongxiang has with the in-fluential regional and local Forestry Bureaus in this part of China and his remarkable talent of approaching and instantly being on good terms with the local population.

After some reconnaissance tours by Kang Yongxiang, we did most of the field work in 2008-2010. The results of the whole project have been present-ed in a paper: Yongxiang Kang & Erland Ejder, Magnolia sprengeri Pamp.: Morphological variation and geographical distribution. Plant Biosystems, Vol 145, No. 4, December 2011, pp. 906-923. Thus, for those interested in the details, I refer to this paper – the present article is just a short résumé meant to give a general orientation of the work and the main results.

GeographyLet’s first have a look at the geographical facts.

The map on the right shows the combined results of a number of field tours and, to the left, each dot marks a locality comprising one to many individual M. sprengeri specimens.

1. The western end of the mighty Qinling mountain range protruding east-wards from the High Tibetan plateau. The maximum altitude is almost 4000m, but M. sprengeri is found only up to about 1800m.

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2. The two western localities are on the north slope of the Qinling moun-tain range which is the northernmost Magnolia habitat of central China. Just to the north the loess soil plains start, windblown mineral soils from the northern steppes very unsuited for magnolias. The eastern dots are on the south slope of the Qinling Mountains; they have a milder climate than the northern slope. Actually, this range is the divide between north-ern and southern China, a climatic border and an agricultural one: to the north is wheat-growing country; to the south, rice. Parts of this area are also Giant Panda habitats. The best known panda habitats are in north-western Sichuan, but there is a group of around 300 pandas in Shaanxi province also –located where the digit 2 is on the map.

3. By the way, the 19th century plant collector Paul Guillaume Farges explored the south slope, just south of the digit 3 in the map.

4. The Shennongjia Mtns. form the eastern end of Daba Shan. It is rugged and in parts difficult to access. Many areas were logged and encroached upon as a result of mountain farming from 1950 to 1980; but the land has since been proclaimed protected and is an important conservation area.

5. Wudang Shan is of interest as the locality of the type specimen of M. sprengeri, due to reports of exploration made by the Italian missionary Padre Cipriano Silvestri in 1912.

6. Central China is bisected by the mighty Yangtze River (Chang Jiang in Chinese). It is a transition area between the northern and southern parts of the M. sprengeri area of distribution. Wilson’s collection of the ‘Diva’ clone was done between 6 and 8, but the exact location has never been possible to pinpoint.

7. The border between West Hubei province and Chongqing (formerly the eastern part of Sichuan, but now an independent region), where we tested our assumptions of M. sprengeri distribution and, indeed, found many in-teresting specimens. The westernmost locality in area 7 is “Metasequoia land”, where the sensational discovery of living specimens of Metasequoia glyptostroboides was made in the 1940s.

8. The mountainous region in S. Hubei, near the border to Hunan was found to be rich in Magnolia. The border runs along the top of a mountain range and there are definitely some M. sprengeri also across the border in the very north of Hunan.

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MethodsA couple of complicating factors for the field study of these magnolias are the following:

1. It is almost impossible to find wild-growing magnolias during most of the year. They are rare and they blend in well with other trees, but the exception is during flowering time, March-April, when the extravagant flower displays reveal their locations, even when viewed over long dis-tances. You can stand on a mountainside and search the opposite slope with or without binoculars. This also means that a thorough characteriza-tion of a specimen requires a re-visit in autumn when leaves and fruits are available for study. We have always recorded coordinates and also in many cases collected graftwood to establish many specimens in “clone archives” for further study of morphological characters, DNA and devel-opment.

2. The other complication is the distinction between wild-growing and cultivated specimens. The long- recognized medical value of magnolias is the reason they are so often found as cultivated plants at mountain farms in western and central China. If a plant cultivated at a farmhouse is of local provenance, it is still valuable as it is a representative of the local cli-mate and ecology, although information about altitude adaptation might be lost. In such cases we have always done thorough interviews with the local residents. The picture that emerges has practically always been that the plant has been moved as a sapling from a nearby mountain. Never has it been said to be the result of seed sowing. This might seem surprising, but, obviously, very few plants are needed and it is easier and quicker to transplant a natural sapling.

Sometimes we saw occasional old magnolia trees that used to be part of natural forest. As more and more land was claimed for cultivation, the forest was felled, and sometimes the magnolias were spared. Now they are found growing close to the little fields and farm buildings in the moun-tains, leaving the impression that these old magnolias had been planted by the farmers.

The population of China more than doubled between 1950 and 2000 and in the mountainous areas very marginal land on steep slopes and high altitudes was brought into cultivation. Amazingly steep slopes are some-times cultivated where there cannot possibly be any chance of a sustain-able agriculture. Actually, there are emerging signs of a reversed develop-ment with re-forestation and mountain farms being abandoned. Whether magnolias can reclaim their old habitats remains to be seen; it is by no means certain.

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A special situation is when magnolias are growing at old temples. It is well known that Buddhist monks have always appreciated and cultivated flowering trees. Their networks have no doubt facilitated the spreading from garden to garden of particularly attractive Magnolia clones and we have been very wary of taking them as expressions of the local flora.

Climate Climate statistics are readily available for many locations in the provinces of interest, but are usually recorded at population centers in plains and valleys. The natural habitats of M. sprengeri are between 1000m and 1800m altitude and there is naturally a shift in temperatures from the north to the south of the investigated area. However, the difference in altitude is more important than in latitude. The harshest climate seems to be on the north slope of the Qianlong Mountains where, at 1590m altitude, a recording point has reported -5 ºC average January mean temperature and -26 ºC ab-solute lowest temperature recorded (both data for the period 1971-2000). The variations in the microclimate determining what the specimens actu-ally have to cope with must be supposed to be considerable, but no hard facts are available. It would require logging temperatures of individual M. sprengeri trees in the wild – facts we hardly ever know even in our gardens.

Spring frosts sometimes occur in the natural locales during flowering time and we have observed light to medium frost damage of flower tepals on some occasions. This might well be the decisive factor limiting the ad-vancement of the populations to higher altitudes.

Observed characteristicsThe most obvious characteristic is, of course, the flower color and here the results have been astonishing. At one of the endpoints of the interval of variation are the practically white flower with only the faintest pale purple coloring at the lower outside of the tepals and – at the other end – a deep pink (red) color on both sides of the whole tepals. The photos below and at the top of page 7 show a small sample of the material we have investigated.

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In the traditional descriptions of M. sprengeri the number of tepals is given as 12. This is the most common number, but we have found a wide varia-tion, from 6 up to at least 16, also with some variation within the same tree. The photo below shows an example of 15 tepals.

The leaf shape and proportions have earlier been used as an important character. Here, too, we find a considerable variation. The photo at the topp of page 8 shows mature leaves from two different neighboring trees, both with almost white flowers, obviously with very different length/width ratio. A further complication is that the leaf shapes along a fully

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developed shoot vary systematically with the early spring leaves being more elongated than the late season’s more rounded leaves.

In our gardens we often observe that the Magnolia fruits of the Yulania subsection, including M. sprengeri, often have few developed (seed-bear-ing) carpels per fruit, which results in knobby and irregular fruit shapes. If there has been any suspicion that this is caused by less ideal conditions in cultivation in an alien climate, it can now be stated that this phenom-enon is very common in the wild habitats also. As early-season flowering plants, the activity of pollinating insects is probably unreliable and very weather dependent. Also, it is quite probable that lone trees suffer from self-incompatibility problems. We have seen examples of this behavior: big isolated trees flowering prolifically, but setting very few seeds. We have confirmed this behavior by means of a few controlled pollination experiments on cultivated trees.

The habit of growth must be judged where the development has not been influenced by special circumstances. The photo at the top of page 9 shows three relatively mature M. sprengeri specimens. The left one has been al-lowed to develop freely, possibly with a little branch harvest for medicinal buds. The middle one is about 250 years old, but was cut down in midlife and has since re-grown 15 new shoots from the stump. Until 20 years ago buds were harvested high up in the collective crown. The specimen to the right has not been tampered with and is still growing vigorously with an ascending habit. Some specimens we have found have been of a really impressive size, up to 25-30m tall.

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Further work, discussionThe purpose of forming a clone archive has partly been to facilitate the extraction of DNA samples. So far – and accounted for in the detailed pa-per – we have checked the ploidy (number of chromosome sets) by stan-dard cytology methods, chromosome counts in root-tips of seedlings of wild collected seed. As expected, all have been hexaploid. Further work on DNA, such as partial sequencing of chloroplast genomes is now done by Dr. Wang Yaling of the Xian Botanical Garden/Qinling National Park and co-workers and DNA sequence studies by other methods by Profes-sor Kang Yongxiang’s group in Yangling. Results will be published else-where later, but so far it seems the genetic differences between red and white flowering forms of M. sprengeri are very minor, thus not giving any support to the concept put forth by some experts that M. sprengeri should be divided into two different species.

So far, I have given a short résumé of our findings from the field studies. It can be added that it is a huge task in spite of the mentioned improvement in communications. We have, in total, travelled well over 15,000km on our tours and the mountain roads and trails have sometimes been quite challenging—another story in itself. Still, we have, of course, only taken samples from what is really out there; it would take several lifetimes to find them all, especially in this wild terrain. Often, we have acted on in-formation from Forestry Bureaus and local residents and sometimes from probability considerations based on map studies.

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ConclusionsThe rest of this article will cover some of the discussion and conclusions based on the field observations, by necessity very condensed; for a fuller treatment I refer again to the original paper mentioned above (Kang & Ejder 2011).

1. The main finding is the wide variation in all characters we have ob-served. In part, this is understandable due to the very limited material available when the original taxonomic descriptions were made. Several authors, like Spongberg (1976, 1998) and Chen and Nooteboom (1993), have emphasized the need for more wild-collected material. Now that we have this, it is obvious that the variability is much wider than previously recognized.

2. The evolution (over a period of 100 million years) of the flowers of the angiosperms (the flowering plants) has been much more clearly defined in recent years. Magnolias are very old and primitive and, typical for such plants, exhibit, among other characteristics, a very wide diversity in floral structure and organization in comparison to later evolved plants which have a rigid plan of flower architecture (Soltis et al 2007). The flower or-gans are often numerous and intergrading, and spiral rather than whorled arrangement is common. It can be well exemplified by the flowers of the Japanese M. stellata with 6-30 tepals. The consequence is that the number of tepals should be expected – as indeed observed – to be quite variable, between individuals of the same species and even to some extent within an individual specimen. Thus, the tepal number should not be seen as such a strict decisive characteristic as has often been the case when defin-ing different species. This should be born in mind generally in Magnolia systematics.

3. Another reason for the variability is the extreme climatic history and topography during the evolution of M. sprengeri and other magnolias in central China. There has not been any complete glaciation for millions of years, but these magnolias are mountain trees and have always grown on the climatic edge. The mountainous landscape consists of innumer-able peaks and narrow valleys where plants can colonize and adapt to favorable habitats. However, the climatic situation has not been static but very dynamic, with cycles of colder and warmer climate of a frequency of 20,000-100,000 years during the last few million years – as discussed by Hebda and Irving (2004). Direct and detailed records of the cyclic climatic variations have been seen and reported in the stratigraphy of loess soils close to our areas of investigation.

These circumstances are ideal for a rapid genetic evolution by the alternat-ing isolation and merging of local Magnolia populations. It is highly likely

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that very numerous local variations have developed in populations which - for very long times - could not interbreed with other populations due to geographical isolation. We have often seen these situations of very limited gene-flow in our present investigations.

4. The hexaploid status of M. sprengeri and some other species in west-central China (and in the mountains further west) is no coincidence. It has been shown that most of the polyploid magnolias are found in this zone of very active evolution close to the climatic limit. Studies of the flora of subarctic regions in other parts of the world have shown a high incidence of polyploidy in herbaceous taxa and pioneer lignoses (Brochmann et al. 2004).

The meaning of recurrent polyploidisation – now seen as common - is that the evolution of hexaploids has happened in several places and at differ-ent times rather than at one crucial occasion with subsequent diffusion (Soltis et al. 2004). Then the systematics and the unraveling of the his-tory become even more difficult. Another reason for increased variability is thus possible, as the founding taxa taking part in these hybridizations and chromosome doublings can be similar-but not necessarily identical-taxonomically.

5. There has been much confusion around the characters of Silvestri’s type specimen of M. sprengeri (“the original M. sprengeri”), collected at Wudang Shan in NW Hubei in 1912. It was taken early in the year and there are no leaves present and the flower is in a state where the color can not be determined.

So the question whether it had pink or white flowers has been an open one which should, if possible, be settled. We have made a determined ef-fort to find the answer and we are convinced beyond any doubt that it has white flowers - with the usual faint purple nerve on the outside of the tepal. We have arrived at this conclusion by field investigations at and in a very wide area around Wudang Shan. We have found many white M. sprengeri here, but no pink ones. We have interviewed many local people, shown them photographs and discussed the matter; the definite conclu-sion is that only the white variety belongs to NW Hubei.

6. Up to now some authors have suggested one single M. sprengeri species, but the common opinion has been to recognize M. sprengeri var elongata (white) and M. sprengeri var diva (red). However, as pointed out by Spong-berg (1976), the naming rules require a “var sprengeri” if another variety shall be named. The results of our research would indicate that the for-mal naming, therefore, should be M. sprengeri var sprengeri (white) and M. sprengeri var diva (red).

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The Yangtze River is the dominating geographical divider and we find that the white flowering forms are mainly found north of the river and the red-pink forms mainly south of it. Evolution does not follow maps but the Yangtze River valley, especially in the western part of our area, forms a natural barrier of lowland, not suitable for magnolias. In the east, the river valley is increasingly narrower and, indeed, a division between white and red flowering forms is fuzzier.

When setting up simple categories you must expect some borderline cases and we have a few. If we define white flowers as basically white tepals but allow more or less coloring at the base (and a rather fleshy texture of the tepals) and red flowers as basically red but sometimes rather pale (and fleshy or papery texture), the character and geographic distribution distinction in two groups holds up well.

The name “var elongata” was given with reference to the elongated leaves on some herbarium specimens. However, we find that there is no strict correlation between flower color and leaf shape, although elongated leaves are more common north of the Yangtze and broader leaves more common south of the river.

We have, of course, also considered if there might be enough evidence to define two species: M. sprengeri and M. diva, but our conclusion is that there is not. When we wrote the detailed paper no molecular (for example chloroplast DNA) results were available, but later Dr. Wang Yaling has done sequencings of these and other magnolias. The results will be pub-lished later, but so far very small differences have been found within the M. sprengeri material which strengthens the decision to keep it as one spe-cies.

7. In addition to M. sprengeri there is a further group of recognized hexa-ploid magnolia species in the mountainous areas all the way from Bhu-tan to east China: M. campbellii (with possible varieties), mollicomata (often under campbellii), sargentiana (and a variety), dawsoniana, denudata (with one or two varieties). The geographical extension of this distribution is immense but there are considerable similarities morphologically and (as is starting to emerge) in genetic structure. The delimitations between the described species are not always convincing. For example, we have seen features normally associated with M. sargentiana in our sprengeri speci-mens. Some DNA studies are underway by Dr. Wang Yaling, but it re-mains to be seen what the outcome will be. The situation is not surprising with regard to the mechanisms described under 3 and 4. A vast complex with many similarities but differences due to many local geographic isola-tions and repeated hybridizations and chromosome duplications at dif-ferent locations and times must result in a taxonomically very difficult meta-population.

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It is important that no hasty nomenclatural changes are made without a solid foundation. The power of tradition is strong and much frustration and confusion is caused when taxonomic reforms are introduced, there are many examples. Too much splitting into different species and variet-ies is difficult to handle and sometimes the result of a lack of understand-ing of natural variation in and between populations. Too much lumping will not give us the practical guidance we want from taxonomy. In any case it must always be remembered that taxonomy is man’s e ndeavour to handle the different “kinds” of plants. Nature has no inherent species, it is a concept we have invented.

SummarySo a final summing up might be as follows:We have determined the flower color of the M. sprengeri type specimen. We have unveiled the multitude of M. sprengeri forms still growing in west-central China.We have found a large number of beautiful clones. We hope we have pre-sented the arguments for a more open view on variation in Magnolia char-acters – in M. sprengeri and generally.

There are always open questions left but some will be answered by con-tinued work together with the groups of Professor Kang Yongxiang and of Dr. Wang Yaling.

And we have had a really great time and countless adventures!

.Thanks are due to Richard Figlar for several useful comments.

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References (An extended reference list is found in Kang & Ejder 2011).

Brochmann C, Brysting AK, Alsos IG, Borgen L, Grundt HH, Scheen A-C. 2004. Polyploidy in arctic plants. Biol J Linn Soc 82: 521-536.

Chen BL, Nooteboom HP. 1993. Notes on Magnoliaceae III: The Magno-liaceae of China. Ann Missouri Bot Gard 80: 999-1104.

Gardiner JM. 2000. Magnolias. Portland, Oregon: Timber Press.

Hebda RJ, Irving E. 2004. On the origin and distribution of magnolias: Tectonics, DNA and climate change. In: Channell JET, Kent DV, Meert JG, editors. Time scales of the paleomagnetic field. Washington DC: Am Geophys Union pp. 43-57.

Kang YX, Ejder E. 2011. Magnolia sprengeri Pamp.: Morphological varia-tion and geographical distribution. Plant Biosystems 145: 906-923.

Savage PJ Jr. 1969. The goddess of Chanyang Hsien. Magnolia 6: 1-5. (Ed-ited and reprinted in Magnolia 16(2), 1980).

Soltis DE, Soltis PS, Tate JA. 2004. Advances on the study of polyploidy since plant speciation. New Phytol 161: 173-191.

Soltis DE, Chanderbali AS, Kim S, Buzgo M, Soltis PS. 2007. The ABC model and its applicability to basal angiosperms. Ann Bot 100: 155-163.

Spongberg SA. 1976. Magnoliaceae hardy in temperate North America. J Arnold Arbor 57: 250-311.

Spongberg SA. 1998. Magnoliaceae hardy in cooler temperature regions. In: Hunt D, editor. Magnolias and their allies. Sherborne, UK: Int Dendro-logical Soc and The Magnolia Soc.

Treseder NG. 1978. Magnolias. London: Faber and Faber.

Wilson EH. 1980. Magnolias. Magnolia XVI: 5-26. (First and posthumous publication of a manuscript from about 1930).

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Journey to the U.S. National Champion Magnolia virginianaGary Knox, Professor of Environmental Horticulture, University of Florida, Quincy.

I have thoroughly enjoyed reports of MSI members’ trips to exotic places to view rare magnolias in the wild. Most of these expeditions take place in remote areas far from the comforts of civilization. The stories of these intrepid adventurers are always inspiring and I admire them for suffering great hardships to reach and view rare magnolias.

This story is nothing like that.

Usually, urbanization involves clear-cutting all plant life, often leaving only weedy natives and exotics growing in the gaps between neighbor-hoods. But occasionally the “wild” survives, even in the heart of civiliza-tion. Minutes from a major interstate highway, amidst four million people, a stone’s throw from views of downtown Tampa’s modern buildings, and a short drive from Ybor City, the historic café and entertainment district of Tampa, grows the largest documented sweetbay in the U.S., and prob-ably the world.

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The story of my journey begins February 2012 when I was addressing about 300 landscape professionals in Tampa, a major city in central Florida. As I was regaling them with details about exciting new plants (emphasiz-ing magnolias), one member of the audience emailed me, asking if I’d like to see the National Champion sweetbay. Unfortunately, I did not read his email until I had returned home, four hours and hundreds of miles later.

Jason’s discoveryThe emailer was Jason Zysk, a Certified Arborist operating Greenworks Inc. in Tampa, Florida. Jason is the hero of this story because he is the one who discovered, or rather, recognized, this monumental remnant of the wild in the middle of a big city and then nominated it as a champion tree.

In June 2010 Jason was diagnosing problems on some residential citrus trees for a client in one of the more modest Tampa neighborhoods. Dur-ing his visit, he caught a glimpse of a massive tree in a neighboring yard and interrupted the client with, “Can you hang on for a minute?” He walked next door and couldn’t believe the size of this tree, identifying it as a naturally occurring sweetbay (Magnolia virginiana), a much beloved but underused Florida native.

As an arborist, he was aware of the National Big Tree Program (http://www.americanforests.org/our-programs/bigtree/), a conservation move-ment to locate and protect the biggest tree species in the United States. Operated by American Forests, a U.S. nonprofit conservation organiza-tion, big trees are ranked by points based on circumference, height and crown spread. Jason knew there were no listed Champion Trees in Tampa, so he did some research, talked to several colleagues and thus determined that this sweetbay was potentially worthy of being included on the Flor-ida Champion Tree list. He worked with the Florida Forest Service, who sent out a forester to measure the tree and forward the measurements to authorities in the state capitol. Subsequently, Jason was contacted with the surprising news that it was not only the biggest in Florida, but the big-gest sweetbay recorded in the U.S.!

My journeyJason’s story about the National Champion sweetbay inspired partner Ken Beebe and me to view this magnificent remnant of the “wild.” From our Tallahassee home, we traveled 250 miles south via Interstates 75 and 275 to the Tampa area. The Hillsborough River runs through this city; our destination was one of the neighborhoods bordering the river just min-utes off Interstate 275. In the middle of this neighborhood, in total ob-scurity, grows the largest recorded Magnolia virginiana in the U.S.--and probably the world.

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The neighborhood is a collection of modest 1940s bungalows, definitely “in transition” (in a positive way), with neatly kept homes amidst run-down properties. The huge magnolia is hidden in the back yard of a rental house, screened from street view by a large live oak (Quercus virginiana). The lack of direct view almost convinced me I had the wrong address. De-spite Jason’s assurance that I could safely view the tree, I knocked on the front door of the modest bungalow to get permission and be sure I wasn’t intruding. After no answer to my knocking and seeing a “for rent” sign in

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front, I walked around the side of the house. Before I was halfway back, I stopped in my tracks as I caught view of the smooth, light grey bark on a huge trunk rising skyward. I called excitedly to Ken to come around and bring the camera, and we examined the mammoth tree. The U.S. National Champion SweetbayIts 2010 records at the National Champion Tree website ( http://www.americanforests.org/our-programs/bigtree/) proclaim it 61 ft (18.6m) tall, 60 ft (18.3m) wide and with a trunk girth of 199 in (505.5 cm). I believe every inch of its description! The immense sweetbay lies at the juncture of two backyards, seemingly ignored by residents of both properties.

While the National Champion sweetbay is an over-mature tree on the downside of life, much of it is still in good shape. It is composed of a sin-gle bole from which several main trunks branch, some of them with rather interesting twists, turns, branch stumps, burs and hollows. All branches were fully foliated, but flowers and fruits were notably absent on the tree and only a few old fruits were found on the ground.

Site characteristicsThis native giant is accompanied by an assortment of non-natives that typ-ically invade unkept landscapes in this region of central Florida, if, indeed, they were not originally planted. The main trunk of the sweetbay displays tracings of the vines, creeping fig (Ficus pumila) and pothos (Epipremnum pinnatum var. aureum). Plants at the base include a bed of liriope (Liri-ope spicata) infested with Sword fern (Nephrolepis cordifolia), Camphor tree (Cinnamomum camphora), mother-in-law’s tongue (Sanseviera trifasciata)

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and areca palm (Dypsis lutescens) surrounded by a thin lawn of St. Augus-tine grass (Stenotaphrum secondatum). A few root sprouts of sweetbay also are present, though there is evidence they had been pruned back regularly in the past.

Although the topography is flat, the soil around the tree’s base showed evidence that recent rains had pooled in the area, and the soil appeared darkly or-ganic. A carpet of fallen leaves assures a constant supply of natural mulch and organic matter. Prior to urban develop-ment, native soils of this area were sandy, acidic and prone to high water tables. A few large pines, oaks and southern mag-nolias (Magnolia grandiflora) dot the neighborhood. There is little other native vegetation that hints at the area’s possible original ecosystem of flatwoods, swamps, marshes or bayheads, of which sweetbay is a major component. However, we not-ed no other sweetbays nearby until we approached the river about a half mile away.

We spent the better part of two hours photographing and examining the colossal sweetbay. After completing our homage to this tree, I gave it a last, fond look and got back in the car. To celebrate our journey and honor this magnificent tree, we traveled just a few minutes away to find a de-lightful café and refreshing beverages in historic Ybor City. As I sipped my drink, I thought, “This is my kind of plant botanizing!”

ReflectionsIt is a miracle that this huge tree survived the clear-cutting, grading and surrounding construction of houses and paved roads in the 1940s, not to mention more recent aspects of urbanization. Magnolia expert Dick Fi-glar postulates that many similarly massive sweetbays had been plentiful in the past, but were logged or cut as a result of the development along the Gulf Coast of Louisiana, Mississippi, Alabama and Florida. Still, there is the possibility that other monster sweetbays might still remain in the more remote natural areas of the Gulf Coast--or maybe in the midst of

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other cities. Hopefully, this story will inspire others to similarly seek out these grand champions.

In the meantime, we can collectively honor this champion sweetbay. Though it may be unappreciated by residents of its densely-populated setting, this enormous sweetbay stands as a silent testament to the vigor, resilience and adaptability of sweetbay, and of magnolias in general. The exact whereabouts of this champion tree shall remain anonymous since it is located on private property. However, I am told the property recently

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underwent foreclosure. Perhaps some sympathetic magnoliaphile may want to step forward to purchase the property and preserve this treasure . . . if so, let me know!

AcknowledgementsMany thanks to Jason Zysk, Greenworks Inc., for telling me his story, showing me the location of this National Champion sweetbay, and espe-cially for nominating it for the National Register of Big Trees.

Thanks also to Ken Beebe for humoring me with a trip to visit this tree and for assisting with photography.

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The Jury magnolias from New ZealandAbbie Jury, Tikorangi, The Jury Garden

The Jury magnolia reputation has been built on a small number of named varieties. Felix Jury only ever named eight of his own breeding – Magno-lias ‘Apollo’,’ Athene’,’ Atlas’, ‘Iolanthe’,’ Lotus’,’ Milky Way’, ‘Serene’ and Vulcan™ . We don’t include the variety M. ‘Mark Jury’ in that list because it arrived here as a seedling of Lanarth purchased from Hilliers and all Felix did was to grow it and, in due course, name it. There is no record of how many seedlings he raised. Mark’s comment is that it wasn’t a huge number and he guesses somewhere between 50 and 100 in total. Mark curbed his father’s suggestion of naming a few more because they were too close to ones already selected, although we have a few fine sister seed-lings from those breeding lines in the garden here.

In his turn, Mark has raised many more controlled crosses. He has never kept track of the number, but a rough guess brings him around the 1000 total of deciduous magnolias grown to flowering size so far. Of those he has named a grand total of four. He is discerning. All were chosen because they represented a breakthrough in some aspect: an ability to produce flowers on young plants, not grow so rapidly as to indicate that they will become forest giants, propagate relatively easily and flower reliably every year, while setting buds down the stems to prolong the season.

Magnolia Black Tulip® was selected because it sets flowers freely on young plants and achieves a depth of solid dark color with heavy textured petals in an attractive goblet form which holds its shape. M. ‘Burgundy Star’ of-fered a totally different habit of growth, strongly fastigiate, and the large star-shaped blooms over a prolonged period are a purer red at their best. Being three parts M. liliiflora ‘Nigra’, he hoped it would also prove hardier and maybe hold its color in colder climates.

Felix® is our personal favorite so far. It is big, up to 30cm (12 in) across. It is very showy. With us, it can appear a rich red, but even when the color gets bleached out in colder climates, it retains a good depth of deep rosy pink. It was everything that Felix Jury himself was trying to breed – a big, rich- colored M. ‘Iolanthe’ – and he lived long enough to see it bloom. This is a cultivar that we think is just going to get more spectacular with age and size.

This year will see the first release of Mark’s newest cultivar called Honey Tulip™. It is a golden honey version of Black Tulip® and represents a breakthrough in flower form and petal substance in the yellows. It retains its color through the flowering season where the comparators (Magnolias ‘Yellow Fever’,’ Sundance’ and ‘Hot Flash’) all become increasingly pale.

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For our climate, it is particularly significant that it flowers on bare wood where most of the yellow hybrids flower at the same time as they come into leaf. It is also less vigorous, which is to its credit, given that the yel-lows tend to compete with timber trees here in their rate of growth.

What takes time to sort out is how well these magnolias will perform over-seas in different climates. M. Vulcan™ has been patchy at best internation-ally and washes out to a muddy purple in cold climates. M. ‘Iolanthe’, too, has not matched up in many overseas locations. Yet, here in New Zealand it is a flagship magnolia. The original plant is now somewhere over 50 years old and planted in the most prominent spot in our garden. Year in and year out it takes our breath away with its sheer magnificence. There is a lot of trial and error involved in how these plants perform overseas and we have been particularly delighted to see that M. Felix® seems to be measuring up across a range of climates.

Mark continues with breeding deciduous magnolias. The quest here is for a yellow M. ‘Iolanthe’ (in other words, a very large cup and saucer bloom in yellow). He is after pure reds which lose the magenta hue common to the first generations of new hybrids and he is getting very close to it. There is certainly room for an improved M. Vulcan™ which would bloom with better color in other climates and fade out with more grace as its flowering season draws to a close. There is a way to go yet in a pure purple.

Magnolia Honey Tulip™ is a soft golden version of M. Black Tulip® scheduled for release in 2013. The rounded flower form and heavy textured petals appear to be an advance in the yellow magnolias. (photo by Sally Tagg)

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The process here is to grow seed to a large enough size for planting out which usually takes about 18 months. They are then planted wherever there is space. Our shelter belts (wind breaks) are rows of trial plants, in-cluding magnolias. Some are in groves, some edging a stand of native forest, some lining our road verges and he has now resorted to rows in the open ground. From time to time, Mark heads out with the chainsaw. If the seedlings haven’t flowered by five years old, they get the chop. If it be-comes clear that a cross is of no particular merit, the batch will be felled. If one is looking very promising, others will be cleared to give it space. Over time, the first groves have been thinned down from about 120 to the best 20, which will remain in situ. Because, of course, if you are only naming about four out of a thousand, there are a rather large number of also-rans which are too good to cut out, but not good enough or sufficiently differ-ent in the eyes of the breeder to release.

Venturing into the michelia branch of the magnolia family has been much more recent. The first crosses only go back about 17 years but the turn-around is much faster so the total number raised is already larger than the deciduous magnolias. One has been widely released and is on the market as Fairy Magnolia® Blush. The next two are scheduled to be released this year – Fairy Magnolia® White and Fairy Magnolia® Cream.

The decision to brand these with the trademarked name of Fairy Mag-nolia® was made by our agent, Anthony Tesslaar Plants. With the reclas-

Magnolia ‘Iolanthe’ is one of our star performers here and has achieved considerable stature after 50 years. It has necessitated relocating the vegetable garden.

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sification by taxonomists of Michelias to Magnolias, it seems important to highlight the difference between these and the larger, evergreen grandi-flora types.

Michelias flower in two to three years from seed so it is possible to use them for further hybridising and to see directions quickly. However, there is an additional hurdle. Deciduous magnolias are usually budded and it is only the occasional one which falls at the propagation hurdle. Michelias are much more of a mass market proposition and have to propagate easily from cutting and in tissue culture. We have a far higher fall out rate when it comes to trialling for ease of propagation. We were disappointed when a green-yellow full sister to Fairy Magnolia® Blush, which had very dis-tinctive large green buds encased in brown velvet, fell at the last hurdle. It’s a good plant. It just doesn’t propagate reliably. With hindsight, it is a little sparse in foliage, too, so maybe it is to the good that it didn’t make it to international release.

Similarly, the colored varieties appear to be problematic when it comes to propagation. The breeding program has yielded some good pure yellows which are easily on a par, color-wise, with the yellow deciduous magno-lias. None so far have propagated reliably. Even more disappointing have been the purples. Hopes are raised when a plentiful number of flower buds open to good-sized, distinctive purple flowers, but none of these seedlings has so far passed the propagation test with high enough per-

While Mark is getting some interesting colors in the michelia hybrids, none has yet passed the propagation trials.

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centages. If they are reluctant to strike from cutting, it appears that they are equally problematic in micropropagation.

Fragrance has been another issue. Even when using two strongly fragrant parents, a large proportion of the offspring are bereft of any scent at all. We have many visually splendid plants, some representing real break-throughs in form or flower but doubt the willingness of the buying public to embrace a michelia with no scent. Mark has been backcrossing some of these to scented species to see if he can get the fragrance back.

Others are rejected because they are too fertile, setting far too much seed, which will lead to a scraggly plant over time, and a scraggly plant with weed potential in some conditions. Some crosses have simply been too vigorous in growth to contemplate them as garden plants of merit no mat-ter how lovely the blooms.

New Zealand’s borders are now well and truly closed to any imports of new species of any genera so Mark has not had access to recent introduc-tions. In fact he is working on a limited range – mostly M. doltsopa, M. figo, M. laevifolia and M. maudiae. M. alba and M. champaca – have proven to be blind alleys so far and the obscure and as yet unidentified wild-collected michelia species brought back from Vietnam by the late Os Blumhardt has little merit or breeding potential. Mark observes that he has not seen other new species that he covets or that he thinks will add much of significance to the hybrids, so the closed borders have not been the problem that he initially feared. He has ruled out using allied plants such as Mangletias because they lack the floriferous characteristic that is a bottom line for any hybrid. By this stage he is down to about the sixth generation of crosses and back crosses using the sought-after characteristics of favored species and hybrids, so the genetic makeup of individual hybrids has become in-creasingly complex.

Fairy Magnolia® Blush brought consistent pink coloring into the range along with bushy growth and floriferous characteristics over a long sea-son. The natural bushiness and the ability to take hard trimming are both important characteristics. The early M. doltsopa x foggii crosses from Os Blumhardt (particularly ‘Mixed Up Miss’ and ‘Bubbles’) make splendid juvenile nursery plants but as they mature, they become leggy and open and most people would not look twice at them. We have had many seed-lings the same and discard any which make only tip growths. Blush has a light and pleasant scent and, despite having doltsopa and figo in its par-entage, it has proven much hardier in the US than we dared to hope and appears to be coping as low as zone 6 with winter protection and com-fortably dealing with zone 7b conditions through the years of pre-release trials in the USA. It is hard to breed the perfect plant – the foliage can be

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a little more olive green than we would like and it would be good to get a larger, pinker bloom, but it is maturing well here.

Fairy Magnolia® Cream, to be released this year, is similar to Blush in breeding and performance, but with desirable brighter green foliage and a very strong fragrance. Its peak flowering season extends into months and the blooms are a little larger than Blush, measuring at least 10cm across.

Fairy Magnolia® White is from a different breeding strain. It has been selected from a very consistent run of seedlings which we have long re-ferred to as the Snow Flurry series. It is one of the earlier flowering mi-chelias, opening in winter, and with a higher proportion of M. doltsopa it is not likely to be as hardy in cold climates as Blush and, we hope, Cream. Where climate and space allow, we think it should prove to be a big im-provement on existing doltsopa types. It has smaller leaves and wonder-ful velvet brown buds opening to the purest of white starry flowers with excellent fragrance. It is much bushier in habit and has never shown the tendency to defoliate after flowering which can be problematic with some doltsopa types (and indeed with many M. laevifolias here). While it forms a plant of some stature (maybe 5m x by 4m, or 16 ft x 13 ft, if not trimmed), it is not going to become a giant like the M. doltsopa, which now takes up a greater area than an urban house plot in our park.

Fairy Magnolia® Blush clips very successfully. These plants are kept to this size with trimming in late spring and a light follow-up in late summer.

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In recent years, we have wound up the wholesale and retail nursery here in order to concentrate on the garden and plant breeding. At the rate he is going, Mark may even-tually end up naming and releas-ing a few more cultivars than his father, but the selections will have been made from trials involving a much greater number of cultivars.

www.jury.co.nzhttp://www.facebook.com/the-jurygarden Twitter: @tikorangi

Felix®, bred by Mark, fulfilled the magnolia breeding ambitions of his father, Felix Jury. It is heartening to hear reports of how well it is performing internationally.

Fairy Magnolia® Cream has very fragrant, large cream flowers over a long season and will be released internationally in 2013. (Sally Tag)

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Diseases and disorders of Magnolia species in the southeastern United StatesGary W. Knox, University of Florida, Department of Environmental Horticulture, North Florida Research and Education Center Mathews Paret, University of Florida, Department of Plant Pathology, North Florida Research and Education Center Amy Fulcher, University of Tennessee Knoxville, Department of Plant SciencesWilliam E. Klingeman, III, University of Tennessee Knoxville, Department of Plant Sciences

Magnolia species are widely used in southeastern U.S. landscapes because of their beauty, usefulness, low maintenance and broad adaptability to the region’s climate and soils. Six Magnolia species are native to the region (Magnolia acuminata, M. fraseri, M. grandiflora, M. macrophylla, M. tripetala and M. virginiana) and many non-native species and hybrids have been introduced. A review of commercial wholesale nursery production in twelve southeastern states found the native M. grandiflora (southern mag-nolia) is the most widely grown--in168 nurseries--because its cultivars are heavily favored for landscape use (Knox 2012; Knox et al., 2012a). Other widely produced species are the native M. virginiana (sweetbay), found in 65 nurseries, followed by the non-native Magnolia stellata (star magnolia), in 47 nurseries, Magnolia ×soulangeana (saucer magnolia) and similar hy-brids, in 16 nurseries. Six other species also are produced.

Magnolias are considered to be “trouble-free” with few pests and diseases under most landscape conditions (Dirr, 1998). A number of compounds in Magnolia species exhibit antimicrobial, insecticidal and nematicidal prop-erties (Kamikado et al., 1975; Li et al., 2009; Nitao et al., 1991). Nonetheless, a wide array of pests, diseases and disorders are reported on Magnolia species in the southeastern U.S. (Knox et al., 2012a; 2012b). Pests, diseases and disorders on magnolia can cause significant economic or aesthetic losses.

This article focuses on major plant diseases and disorders affecting Mag-nolia species in landscape settings, along with management recommen-dations. Many of the management strategies for diseases and disorders ultimately relate to plant health, landscape placement and environment. Weather may be beyond control, but magnolias can be placed in locations that favor their growth and they can be cultivated in a manner that mini-mizes disorders and diseases; for example, by drip irrigating rather than overhead irrigating, which can wet leaves and increase incidence and op-portunity for foliar diseases. When management calls for use of specific pesticides, these tools should be utilized properly and legally, noting that they may only be available for specific species, areas, uses or applicators (such as professionals only).

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Common diseases of Magnolia

Verticillium wilt, Phytophthora root rot and several foliar pathogens are the primary causes of disease on magnolia. No canker or virus diseases are reported.

Verticillium wilt. This disease is caused by Verticillium albo-atrum Reinke & Berth and Verticillium dahliae Kleb., which are vascular pathogens of many ornamental shrubs and trees, including Magnolia (Pataky 1997). Verticil-lium wilt causes leaf and branch dieback often at one side of the tree. Vas-cular discoloration can be noticed on infected plants. Symptom progres-sion may be slow, but the plants can completely wilt and die in 1 to 2 years. Sometimes large areas of cambial tissue die from infections by the fungus and opportunistic fungi such as Nectria spp. (Fr.) Fr. develop in elongated cankers (Chatfield et al., 1996). The characteristic symptom for Verticillium wilt is the discoloration of xylem and cambial tissues, visible as streaks in affected wood (Pataky 1997). However, other diseases and stress factors can also cause these symptoms, and hence a definitive confirmation is re-quired from a diagnostic lab.

Development of Verticillium wilt is favored by factors that stress roots, including wounding and prolonged drought. The fungus penetrates through root-wounds or directly into host tissues (Pataky 1997). Plugging of the vascular system by the fungal organism, restricts water and nutrient movement, leading to plant wilting. The fungus survives in soil as long-lived microsclerotia that can easily spread by wind, soil movement and on equipment. Verticillium spp. can survive in soil for many years. In addition, many weedy plants are also susceptible hosts; therefore, the cycle of con-taminated soil is hard to break.

Management. Avoid stressful conditions for the plants including over-watering, drought and root-wounding that will facilitate Verticillium spp. infection. Avoid planting in areas with previous outbreaks of Verticillium wilt. Fungicides are not effective in management of Verticillium wilt.

Phytophthora root rot. Phytophthora cinnamomi Rands causes this root rot disease. Symptoms include yellowing of leaves, sudden wilting, prema-ture leaf drop, slowed shoot growth, limb dieback and plant death. In-fected plants typically have discolored feeder roots.

Phytophthora cinnamomi survives as hyphae in infected roots and resting structures known as chlamydospores in plant debris and soil (Hagan 2001). This fungus is easily and quickly spread by contaminated water. Root infection can be common and severe if soil is saturated.

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Management. Avoid placing magnolias in areas that allow water to pool. If plants are irrigated, water only when needed and allow soil to dry be-tween irrigations.

Foliar diseases. Bacterial leaf spot, Xanthomonas sp., is a relatively new dis-ease found almost exclusively in commercial nursery production (Dank-ers 2012). Based on the time of the year and conditions prevalent during disease occurrence, high rain and strong wind conditions, as well as heavy overhead irrigation, easily move the bacteria from plant to plant. The bac-terial pathogen can enter through wounds, stomates and hydathodes. Symptoms of bacterial infection vary, but usually start as small necrotic lesions with a yellow halo region and can progress to severe blighting under ideal environmental conditions (Figure 1).

Bacterial blight is caused by Pseudomonas syringae pv. syringae Van Hall and Pseudomonas cichorii (Swing.) Stapp. (Miller 1976). These Pseudomonas spp. cause leaf spots (Mullen and Cobb, 1984) similar to bacterial leaf spot on magnolia (Hagan 2001). The disease is characterized by small necrotic spots with a yellow halo (Figure 2). It is difficult to separate the symp-toms of bacterial blight from bacterial spot. However, bacterial blight usu-ally occurs during cooler and wet weather conditions. Splashing water and overhead irrigation help spread the disease from infected to healthy leaves. Both Pseudomonas species are aggressive pathogens on southern magnolia.

Figure 1. Bacterial leaf spot, Xanthomonas sp., starts as small necrotic lesions with a yellow halo region and can progress to severe blighting under ideal environmental conditions. (Paret)

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Anthracnose (Colletotrichum gloeosporioides Penz) causes large circular spots towards the margins of magnolia leaves (Figure 3) and can lead to premature leaf drop (Hagan 2001). Disease symptoms include a burned appearance or angular spots that are surrounded by a yellow halo (Hagan 2001). The upper surface of the spot develops black, blister-like fruiting bodies (acervuli). As the disease progresses, a pink mass of spores will ooze from the fruiting bodies. Splashing water spreads the spores to new leaves. Warm, humid and wet conditions favor disease development. The fungal organism can overwinter in dead leaves and branches. The disease is most commonly reported on southern magnolia.

Figure 2. Bacterial blight is caused by Pseudomonas syringae pv. syringae Van Hall and Pseudomonas cichorii (Swing.) Stapp. ) and cause leaf spots similar to bacterial leaf spot on magnolia. (Paret)

Figure 3. Anthracnose, Colletotrichum gloeosporioides Penz, causes large circular spots towards the margins of magnolia leaves. (Paret)

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Algal leaf spot, Cephaleuros virescens Kunze, is caused by a parasitic algae (Vann 2007). Commonly seen on southern magnolia, the key symptom of algal leaf spot is the formation of raised blotches on the leaves (Figure 4). The raised blotches will develop a velvety appearance and leaf tissues be-neath the spots die. Premature leaf drop can result from severe infection. Algal spores have the ability to swim in water on plant surfaces. Continu-ous rain during warm and windy conditions serves as a major factor in the spread of the spores. The algae may survive winter on infected leaves and twigs, resulting in repeated infection during following years.

Pestalotiopsis leaf spot of magnolia (Kauffman 2011), Pestalotiopsis spp. Steyaert, appears as unique circular spots with necrotic centers and black borders (Figure 5). Fungal spores from infected leaves and plant debris are spread by wind and water movement. This leaf spot usually occurs during cool weather.

Phyllosticta leaf spot, Phyllosticta magnoliae Sacc., develops as small black spots on the upper leaf surface (Hagan 2001; Pataky 1997). As spots de-velop, their centers turn off-white and borders become purple to black. Black fruiting bodies (pycnidia) appear in the center of these spots. The pathogen is spread to new leaves by splashing water. Warm, humid and wet conditions favor disease progression. Although it is not common, this disease may appear on southern magnolia.

Figure 4. Commonly seen on southern magnolia, Algal leaf spot, Cephaleuros virescens Kunze, causes raised blotches on the leaves. (Paret)

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Powdery mildew on magnolia is caused by at least two species, Micros-phaera alni DC. ex Wint. [M. penicillata (Wallr.) Lév.] and Phyllactinia corylea Pers. ex Karst. [P. guttata (Wallr.) Lév.]. This disease commonly occurs on saucer and star magnolias. Disease symptoms are white powdery patches on the top section of the leaves (Figure 6; Hagan 2001). The entire leaf sur-face may develop these white patches during severe infection. In addition, both leaf curling and plant stunting can occur. Powdery mildew fungi overwinter as hyphae (fungal strands) in dormant buds or as spores in

Figure 5. Pestalotiopsis leaf spot of magnolia, Pestalotiopsis spp. Steyaert, appears as unique circular spots with necrotic centers and black borders. (Paret)

Figure 6. Powdery mildew commonly occurs on saucer and star magnolias and appears as white powdery patches on the top section of the leaves. (Paret)

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fruiting bodies (cleistothecia) on fallen disease leaves. During the spring to early summer, spores are spread by wind. While primarily an issue in nursery production, this disease is favored by warm to hot days and cool nights with dew formation on leaves. Overcrowding of plants and lack of aeration also contribute to disease occurrence.

Management. Most foliar diseases develop only when leaves are frequent-ly wet, as during a prolonged rainy period or with frequent use of over-head irrigation, as is common in container nurseries. If plants are watered with sprinklers, irrigation should be managed to avoid leaf wetness dur-ing overcast conditions, at night and other times when the pathogen may be present. The spread of anthracnose, Phyllosticta leaf spot and algal leaf spots can be prevented by removing infected leaves early in disease devel-opment. Selective pruning to thin the canopy can improve air movement and light penetration, making conditions less favorable for Pestalotiopsis leaf spot, powdery mildew and algal leaf spots. If environmental condi-tions for infection persist, copper-based fungicides can be used to manage bacterial leaf spot and bacterial blight. Other fungicides may be used to manage anthracnose, Phyllosticta leaf spot and powdery mildew.

Common abiotic and wildlife disorders of MagnoliaSome disorders resemble pest or disease damage or may render magno-lias more susceptible to pests and diseases.

Winter burn. Evergreen and semi-evergreen magnolias grown in the up-per South (USDA cold hardiness zones 6b through 8a) commonly exhibit desiccated leaf margins (Figure 7). This winter burn, or scorch, usually is more severe on the side of the plant facing the wind or receiving greater sun exposure (Relf and Appleton, 2009). Evergreen or semi-evergreen magnolias continue losing moisture through their leaves year-round. These magnolias are especially vulnerable to winter burn on warm sunny days when the ground is frozen and plants cannot take up water to re-place that which is lost through transpiration.

Management. A few simple practices help reduce the incidence and/or severity of winter burn. Gardeners should plan for irrigation in the fall to increase the availability of water, especially for newly planted magno-lias that do not yet have extensive root systems. Broad-leaved evergreens should be planted earlier in the fall than their deciduous counterparts (Adkins et al., 2010). This allows roots to become more established before harsh weather and also helps ensure that the plant is optimally hydrated until the soils freeze. Anti-desiccants have not been found to consistently benefit magnolias during transplanting (Relf and Appleton, 2009). Plant-ing evergreen magnolias in an area protected from wind can also reduce the incidence of winter burn.

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Cold injury. Magnolia stellata, M. ×soulangeana and some other magnolias often flower in late winter or early spring. Freezes that occur at bud ma-turity or during flowering will kill or damage buds and flowers, turning flower tepals brown. This freeze damage is unattractive, but the overall health of the plant is not affected and subsequent management is not re-quired.

Bark cracking. Many magnolias are thin-barked and therefore are consid-ered susceptible to bark cracking. In particular, yellow-flowered magno-lias can be prone to bark cracking at the base of the trunk. Excess nitrogen fertilizer or warm temperatures late into the fall season can extend active plant growth. Consequently, the base of the trunk may not sufficiently harden before cold weather (Hartman et al., 2000) and freezing temper-atures may result in bark cracking (Figure 8). Cracked bark usually be-comes evident in the spring, but may occur due to freezing conditions anytime from late fall to early spring.

Figure 7. Winter burn commonly occurs on evergreen and semi-evergreen magnolias grown in the upper South, appearing as desiccated leaf margins. (Fulcher)

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Management. Bark cracking can be avoided by ending liquid or soluble dry fertilization programs early enough to prevent growth. Use of con-trolled-release fertilizers is generally not a problem because most of these products release substantially less nitrogen during cold temperatures. Other management tools include reducing irrigation frequency and vol-ume towards the end of the growing season to slow plant growth and allow them to adapt to cold temperatures. However, allowing the root zones of evergreen magnolias to become too dry during late fall and win-ter can lead to winter burn.

Frost cracking and sunscald. Bark cracking on magnolia also occurs due to frost cracking and sunscald (Clatterbuck and Franklin, 2004). These simi-lar but separate disorders both cause vertical cracks through the bark to the wood. Both often occur on the south or southwest side of a tree since this is where winter temperature fluctuations are greatest. Frost cracking and sunscald are linked to root injury, aboveground wounds and pruning cuts. Inadequate plant hydration is also linked to sunscald, but not frost cracks (Harris et al., 2004; Hartman et al., 2000).

Figure 8. Many magnolias are thin-barked and therefore are considered susceptible to bark cracking. (Fulcher)

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Frost cracking occurs when water in the wood expands and contracts as a result of dramatic temperature fluctuations such as those occurring on warm, sunny winter days with periods of dense clouds or at nightfall (Clatterbuck and Franklin, 2004). Frost cracks are a physical separation of the wood and often they will close and heal.

Sunscald occurs when the same dramatic temperature changes damage or kill the cambium and bark. In winter months, the temperature of the cam-bium receiving direct sun exposure can be 20°C (68°F) or greater when the ambient temperature is at or near freezing; snow exacerbates the tem-perature increase (Sinclair and Lyon, 2005). Sunscald often is not detect-able until spring growth resumes (Harris et al., 2004) when the damage appears as sunken or discolored bark that may later split. If healthy, the tree will develop a callus roll around the wound as the season progresses.

Management. Tree wraps made of insulating paper may mitigate tem-perature fluctuations and prevent sunscald if applied in early winter. Also, avoid large pruning cuts at the bases of trees and large shrubs since some basal bark cracks have been observed in conjunction with large pruning wounds. Remove branches before they become more than 1/3 the diam-eter of the branch or trunk from which they are being removed, in order to minimize the size of the pruning wound and loss of carbohydrates stored in the wood.

Sapsucker damage. Sapsuckers (Sphyrapicus spp.) are a type of wood-

Figure 9. Sapsucker damage is characterized by many uniform rows of holes forming rings around the trunk and large branches as on this saucer magnolia. (Knox).

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pecker native to North America. Sapsuckers peck at trees and feed on sap, bark and small insects that are attracted to the sap (Vann and Robbins, 2008). Sapsucker damage is more common on large landscape trees. It can be distinguished from trunk-boring insect damage by the many uni-form rows of sapsucker holes forming rings around the trunk and large branches (Figure 9), whereas borer damage occurs more randomly and usually with much less frequency. Extensive sapsucker damage creates entry points for disease-causing organisms and boring insects and gener-ally weakens the plants, making plants more susceptible to other types of stresses.

Management. Sapsuckers are protected by federal law and may not be killed or harmed. Recurrent damage may be prevented by wrapping dam-aged areas with netting, burlap or similar materials. Sapsuckers may be repelled by sound-making devices, visual deterrents (e.g. movement of reflective strips or a fake owl) or coating the damaged area with a sticky substance to discourage bird visitation.

ReferencesAdkins, C., G. Armel, M. Chappell, J. Chong, S. Frank, A. Fulcher, F. Hale, K. Ivors, W. Klingeman, A. LeBude, J. Neal, A. Senesac, S. White, J. Wil-liams-Woodward, A. Windham. 2010. Pest management strategic plan for container and field-produced nursery crops in Georgia, Kentucky, North Carolina, South Carolina and Tennessee. A. Fulcher (ed.). Southern Re-gion IPM Center. http://www.ipmcenters.org/pmsp/pdf/GA-KY-NC-SC-TNnurserycropsPMSP.pdf .

Chatfield, J., S. Nameth and N. Taylor. 1996. Verticillium wilt of landscape trees and shrubs. Ohio State University Extension Factsheet. HYG-3053-96.

Clatterbuck, W. and J. Franklin 2004. Bark splitting on trees. University of Tennessee Extension Publication SP630. https://utextension.tennessee.edu/publications/Documents/SP630.pdf.

Dankers, W.A. 2012. Plant Diagnostic Clinic, University of Florida NFREC. Quincy, FL. Personal communication. April 26, 2012.

Dirr, M.A. 1975, rev. 1998. Manual of woody landscape plants. Stipes Pub-lishing L.L.C., Champaign, Illinois.

Hagan, A.K. 2001. Magnolia diseases. 59:231-235. In: R.K. Jones and D.M. Benson (Editors). Diseases of Woody Ornamentals and Trees in Nurseries. APS Press, St. Paul, MN.

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Harris, R., J. Clark and N. Matheny. 2004. Arboriculture: Integrated Man-agement of Landscape Trees, Shrubs and Vines, 4th ed. Prentice Hall, Up-per Saddle River, NJ.

Hartman, J., T. Pirone and M.A. Sall. Pirone’s Tree Maintenance, 7th ed. 2000. Oxford University Press, New York, NY.

Kamikado, T., C. Chang, S. Murakoshi, A. Sakurai and S. Tamura. 1975. Isolation and structure elucidation of growth inhibitors on silkworm lar-vae from Magnolia kobus DC. Agr. Biol. Chem., 39 (4):833-836.

Kauffman, B. 2011. Plant and pest diagnostic highlights. Entomology and Plant Pathology-EPP#60. The University of Tennessee, Extension. Accessed April 26, 2012. http://eppserver.ag.utk.edu/Whats/wh2011/Is-sue-1-2011.pdf

Knox, G.W. 2012. Commercial nursery production of Magnoliaceae in the southern United States. Proceedings of the 2nd International Symposium on the Family Magnoliaceae (ISFM): 262-269. May 5-8, 2009. Guangzhou, China.

Knox, G.W., W.E. Klingeman, M. Paret and A. Fulcher. 2012a. Manage-ment of pests, plant diseases and abiotic disorders of Magnolia species in the southeastern United States: A review. J. Environ. Hort. 30(4):223-234. December 2012.

Knox, G.W., W.E. Klingeman, M.L. Paret and A.F. Fulcher. 2012b. Mag-nolia – Magnolia spp. pp. 181-210. In: Fulcher, A.F. and S.A. White, eds. 2012. IPM for Select Deciduous Trees in Southeastern US Nursery Produc-tion. Southern Nursery IPM Working Group, Knoxville, TN. 321 pp. April 201Li, G.-H., L.-Z. Dang, L.-J. Hong, L.-J. Zheng, F.-F. Liu, L. Li, Y.-J. Liu and K.-Q. Zhang. 2009. Nematicidal activity of honokiol and magnolol isolated from Magnolia tripetala. J. Phytopathol. 157:390–392.

Miller, J.W. 1976. Bacterial leaf spot on saucer magnolia. Fla. Dep. Agric. Consumer Serv. Plant Pathol. Circ. 163.

Mullen, J.M. and G.S. Cobb. 1984. Leaf spot of southern magnolia caused by Pseudomonas cichorii. Plant Dis. 68:1013-1015.

Nitao, J.K., M.G. Nair, D.L. Thorogood, K.S. Johnson and J.M. Scriber. 1991. Bioactive neolignans from the leaves of Magnolia virginiana. Phyto-chemistry 30(7):2193-2195.

Pataky, N.R. 1997. Verticillium wilt disease. University of Illinois Exten-

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sion Plant Disease RPD No. 1010.

Relf, D. and B. Appleton. 2009. Managing winter injury to trees and shrubs. VirginiaTech Extension Publication 426-500. http://pubs.ext.vt.edu/426/426-500/426-500.html.

Sinclair, W.A. and H. Lyon. 2005. Diseases of Trees and Shrubs, 2nd ed. Cornell University Press, Ithaca, NY.

Vann, S. 2007. Algal leaf spot of magnolia. University of Arkansas Exten-sion Publication FSA7553. May 2007. http://www.uaex.edu/Other_Areas/publications/PDF/FSA-7553.pdf

Vann, S. and J. Robbins. 2008. Sapsucker damage on woody plants. Uni-versity of Arkansas Extension Publication FSA7561. http://www.uaex.edu/Other_Areas/publications/PDF/FSA-7561.pdf.

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In Memoriam Professor Zeng Qing-Wen (1963 –2012)

Well-known Magnoliaceae expert and researcher, Professor Zeng Qing-Wen of South China Botanical Garden (SCBG) in Guangzhou, tragically lost his life when he accidentally fell from a 40-meter high research plat-form which had been erected in 2011 into the canopy of the famous Mag-nolia sinica tree in a remote area of Xichou County near Fadou Town in SE Yunnan, China. Over the past year Professor Zeng and his research team had been performing hand pollinations and studying the reproductive mechanisms of this critically endangered species. He had been inspecting fruiting status from the platform when the awful accident occurred on September 20, 2012.

Professor Zeng had long been en-gaged in Magnoliaceae at SCBG as an educator, project leader and collaborator in numerous research initiatives involving all aspects of Magnoliaceae, including conserva-tion, field studies, breeding, orna-mental plant selection and evalu-ation, and other areas. Among the several books he authored was the 2007 Volume 15 “Featured 98 Orna-mental Magnolias”, part of a series of illustrated practical handbooks about landscape plants, and he was associate editor of the very popu-lar and well-known “Magnolias of China” in 2004. He published over 25 papers on Magnoliaceae in various scientific journals, and was author or co-author of six Mag-noliaceae species: Magnolia mulu-nica, Manglietia guangzhouensis, M. longipedunculata, M. pubipetala, M. kaifui, and Michelia guangdongensis. One of those species, Manglietia longipedunculata (Magnolia longipedunculata), he discovered himself while on an expedition to Mount Nankun in May 2000. Since that discovery, only that one population consisting of 11 individuals has ever been found, making M. longipedunculata one of the rarest magnolia species in the world. Another, Michelia guangdongensis (Magnolia guangdongensis) with

Professor Zeng Qing-Wen proudly holds a branch of the stunning Magnolia guangdonensis for the dazzled participants during the SCBG tour of the 2nd ISFM, Guangzhou,

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its spectacular glistening indumentum, is arguably the most ornamental magnolia species discovered during the last 50 years.

Zeng Qing-Wen also played prominent roles in the first (1998) and second (2009) International Symposiums on the Family Magnoliaceae at SCBG as well as for both post-symposium excursion events into Yunnan province where his passion and knowledge of magnolias were as ever-present as his kind demeanor and friendship. He was co-editor of the Proceedings for both symposiums.

His passing is a terrible loss for the world-wide magnolia community. He will be missed.

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The Research Foundation of the Magnolia SocietyThe Magnolia Society Endowment Fund needs your support

Please send your contributions to:The Research Foundation Fund

518 Parker StreetGibson, TN 38338 USA

Contributions are tax deductible in the United States.

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