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Rutgers, The State University of New Je88 Lipman Drive, New Brunswick, NJ 08901-8

Phone: 732.932.5

Cooperative ExtensionEdith Wallace, Ph.D., Master Gardener, Passaic County

Elaine Fogerty Barbour, Passaic County Agricultural Assistant

Fact Sheet FS11

Hydrangeas In The Garden

There are fve dierent species o hydrangea commonly grown in New Jersey and they have dierent owers and cultural requirements. most common hydrangea is the biglea hydrangea with blue to pink owers. It is sensitive to rost and pruning at the wrong time, whichboth result in no owers.

Common Hydrangea SpeciesHydrangea macrophylla (biglea, hortensia or forists hydrangea)is most oten seen with its spectacular pink or blue fowers. Itis used as a garden shrub, in pots by forists, and or resh ordried fowers. The many cultivars o this species may bedivided into mopheads and lacecaps. The mopheads have

large balls o fowers. Lacecaps have a center o small non-showy fowers surrounded by an outer ring o showy fowers.For both types, fower color may be shades o white, red orpurple in addition to pink or blue. Flower color is determinedindirectly by soil acidity. The bluest shades are produced onsoils with a pH o 5.0 to 5.5. Aluminum sulate applicationsmay induce blue fowers. Less acid soil (pH 6.0 to 6.5 or slightlyhigher) is associated with pink fowers. Typical growth is rom3 to 6 high by up to 10 wide. Biglea hydrangea bloomsmainly on stems grown the previous year, thereore springpruning usually results in no fowers. Dead wood should beremoved. Frost may kill the potential fowering shoots. H.macrophylla is hardy to zone 6 and rarely does well in zone 5.

It thrives as a garden plant in seaside communities. HydrangeaEndless Summer is a one o the rost resistant cultivars thatis less likely to be damaged by late spring rosts and bloomsin both spring and summer.

Hydrangea paniculata (panicle or Pee Gee hydrangea) is thelargest o the commonly grown hydrangeas, sometimesreaching a height and spread between 10 to 20 with theappearance o a low-branched tree or large shrub. It is one o

most cold hardy hydrangeas. The white or yellowish-whitfowers, in 6 to 8 panicles, later change to purplish pinkand weigh down the branches. Faded blooms may be pruto make the plant more attractive. Pruning may also be usto maintain the shape o the shrub. This species fowers onew growth so it may be pruned in late winter. Considercultivated varieties i planting this species.

Hydrangea arborescens (smooth or wild hydrangea) is nativthe eastern United States. This ast growing species may rea height and width o 3 to 5. It is sometimes dicult todistinguish rom H. paniculata as the fower clusters ocultivated varieties may be similar. The leaves oH. arboresceare broader and oten bigger with long (1 to 3) petioles.paniculata petioles are to 1 long. Some cultivars have bselected with larger fowers.

As H. arborescens blooms on current growth it can be prunin late winter. It may be drastically pruned (to the groundpruned only to remove old fower heads. Dried fowers mbe used in fower arrangements along with dried H. panicand H. querciolia.

Hydrangea querciolia (oaklea hydrangea) is easy to distinguby the lobed (oak lea-shape) leaves. These leaves maydevelop spectacularly handsome all colors (red, bronze,purple). The plant typically grows 4 to 6 tall and can becquite wide due to its habit o suckering. The fowers, on layears growth, may also be spectacular with white foretsin panicles over 1 long. Native to the southeastern United

8/2/2019 Hydrangeas in the Garden

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Rutgers, The State University of New Je88 Lipman Drive, New Brunswick, NJ 08901-8

Phone: 732.932.5

2011 Rutgers, The State University of New Jersey. All rights reserved.

Comparison of Hydrangeas Species

Cone-shaped ower clusters

H. paniculata H. quercifolia

Native to US

H. quercifolia H. arborescens

Ball-shaped ower clusters

H. macrophylla mophead

Attractive fall coloration

H. quercifolia

Flat-shaped ower clusters

H. macrophylla lacecap H. anomala petiolaris

Grows well in shade

H. quercifolia

Useful as dried owersCut owers when fully mature; hang upside down to dry.

H. paniculata H. quercifoliaH. arborescens H. macrophylla mophead

Multi-stemmed shrubs

H. quercifolia H. macrophylla

Bloom on current growth

H. paniculata H. arborescens

May be grown single stemmed

H. arborescens H. paniculata

Bloom on last years growth

H. macrophylla H. quercifolia

Sequence of bloom

H. anomala petiolaris H. macrophyllaH. arborescens H. paniculataH. quercifolia

For a comprehensive list of our publications visit www.njaes.rutgers.edu February 2Cooperating Agencies: Rutgers, The State University of New Jersey, U.S. Department of Agriculture, and County Boards of Chosen Freeholders. Rutgers Cooperative Extension, a unit o

Rutgers New Jersey Agricultural Experi ment Station, is an equal opport unity program provider and employer.

States, this hydrangea grows well in partial to almost ullshade. It is winter hardy to zone 5. Cultivars are available thathave showier fowers than the species.

Hydrangea anomala petiolaris or climbing hydrangea is a vinethat may grow up a tree or building to 50 or more, clingingby its root-like holdasts. Unlike most cultivated vines it has athree-dimensional eect as branches protrude rom the mainstructure. It has been used to good eect to cover large stumpsand rocks, as a ground cover, and will grow as a shrub. Climbinghydrangea is hardy to zone 4. It grows very slowly in the earlyyears ater planting and more rapidly when established. It preersrich, moist but well-drained soil. It is interesting to grow therelated Japanese hydrangea-vine (Schizophragma hydrangeoides)nearby. This fatter, somewhat shorter vine, blooms later thanclimbing hydrangea. Both species have large (6-10 diameter)fat-topped fowers with outer showy sterile forets and innersmall ertile forets.

Pruning

I dried fower heads are let on the plants over winter,remove them in early spring, cutting back to the rst pair oat buds ound on the stem.

H. arborescensprune in spring

H. paniculatawhen the plant is established it can be cut bin late winter to within 3 o the previous seasons growtheect the shrub is pollarded and the strong upright branchproduced will display the fowers well.

H. quercioliano pruning necessary, except to control size

H. macrophyllaprune out dead stems in the spring. Do n

remove last years wood where the fowers will orm.

Hydrangea ProblemsThe most common problem o hydrangeas is ailure to bloThis most oten happens to H. macrophylla when winters ckills last years growth or over enthusiastic gardeners remoold growth. Choose cultivars oH. macrophylla that are suior landscape use. Hydrangeas received as holiday gits areoten unsuitable or use in the landscape. Also H. querciolfower buds may reeze. Site the plants in a protected spot the landscape or provide winter protection. Hydrangeas arconsidered relatively problem ree.

Photo credits: Page 1 (l): Edith Wallace (r): Pete Nitzsche.