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Smooth Hydrangea, Wild Hydrangea, Sevenbark 'Dardom'

Hydrangea arborescens

Family: Hydrangeaceae (hy-drain-jee-AY-see-ee) (Info)
Genus: Hydrangea (hy-DRAIN-juh) (Info)
Species: arborescens (ar-bo-RES-senz) (Info)
Cultivar: Dardom
Additional cultivar information:(PP14168, aka White Dome)
Hybridized by Kromhout
Registered or introduced: 2002
» View all varieties of Hydrangeas


36-48 in. (90-120 cm)

4-6 ft. (1.2-1.8 m)


36-48 in. (90-120 cm)

4-6 ft. (1.2-1.8 m)


USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

Sun Exposure:

Sun to Partial Shade


Parts of plant are poisonous if ingested

Bloom Color:

White/Near White

Bloom Time:

Mid Summer



Other details:

Unknown - Tell us

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:


Propagation Methods:

From softwood cuttings

Seed Collecting:

N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed

Foliage Color:

Unknown - Tell us

Bloom Characteristics:

Unknown - Tell us

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Where to Grow:

Unknown - Tell us


This plant has been said to grow in the following regions:

Orange Park, Florida

Indianapolis, Indiana

Sioux Center, Iowa

Spring Lake, Michigan

Gardeners' Notes:


On Sep 14, 2009, kellyspiegel from Indianapolis, IN (Zone 5b) wrote:

I have white dome in 2 areas of my yard. The "dome" has never turned white and remains green. The plants appear healthy and have remained at about 3 feet high. Have other growers had this issue? Maybe it should be marketed as "green dome."

Kelly Spiegel
zone 5, Indianapolis


On Dec 9, 2004, lmelling from Ithaca, NY (Zone 5b) wrote:

In "Hydrangeas for American Gardens," by Michael A. Dirr (2004), it says that 'Dardom' is advertised as a new introduction of the species type with largely off-white fertile flowers surrounded and occasionally interspersed with white sterile sepals in clusters of 3 (4). Inflorescences are larger than those of the typical species and carried on strong stems. The leaves are more robust, larger, and thicker.

Notes from Dirr book: The above characteristics are more of less accurate; however, the selection is not from H. arborescens but either subspecies 'discolor' or 'radiata'. The leaves are white beneath (should be green). From a standpoint of adaptability, it will lack heat tolerance, particularly in zones 7-9. Also, the flowers, as shown in advertisements, are similar t... read more