Hydrangea paniculata 'Bombshell'
Common Name: panicle hydrangea
Type: Deciduous shrub
Family: Hydrangeaceae
Zone: 4 to 8
Height: 2.00 to 3.00 feet
Spread: 3.00 to 4.00 feet
Bloom Time: July to September
Bloom Description: White maturing to rosy pink
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Suggested Use: Hedge
Flower: Showy, Good Cut, Good Dried

Culture

Best grown in organically rich, medium moisture, well-drained soils in full sun to part shade. Can be trained as a small single trunk tree, but is best grown as a large, multi-stemmed shrub. May display best shrub form if regularly pruned to a height of 6-10’ tall. This is one of the most winter hardy of the hydrangeas. It thrives in urban conditions. Bloom occurs on current season’s growth, so prune as needed in late winter to early spring.

Larger flower panicles can be obtained by thinning the plants to 5-10 primary shoots. In full bloom, the weight of the flower panicles will typically cause the branches to arch downward.

Noteworthy Characteristics

Hydrangea paniculata, commonly called panicle hydrangea, is a vigorous, upright, rapid-growing, somewhat coarsely textured, deciduous shrub that is native to China and Japan. It typically grows to 8-15’ (less frequently to 25’) tall, and features oval to ovate dark green leaves and upright, sharply-pointed, conical, terminal flower panicles (to 6-8” long) containing both fertile and sterile flowers (mostly non-showy fertile flowers) that bloom from mid-summer into fall.

Genus name comes from hydor meaning water and aggeion meaning vessel in reference to the cup-like capsular fruit.

Specific epithet is in reference to the flowers being arranged in panicles.

'Bombshell' is a dwarf cultivar that typically grows in a rounded mound to only 2-3' tall and to 3-4' wide. It was discovered growing in Boskoop, The Netherlands, in May of 2003 as a naturally occurring branch mutation on Hydrangea paniculata 'Grandiflora'. It is particularly noted for its dwarf/compact shape, abundant star-shaped sterile flowers with elliptic sepals, dense nearly round flower panicles, and free blooming habit. It blooms earlier and longer than most other panicle hydrangeas. Sterile flowers emerge white but slowly mature to a rosy pink, with the smaller fertile flowers being somewhat hidden beneath. Strong stiff stems hold the flower panicles upright with no drooping. Flowers typically bloom from July through September. Ovate, serrate, dark green leaves (to 2 1/2” long) produce generally undistinguished, yellow to purple-tinged fall color. Panicles may be cut for fresh arrangements or for drying, or may be left on the plant where they often persist into winter. U. S. Plant Patent PP21,008 was issued on May 25, 2010.

Problems

No serious insect or disease problems. Some susceptibility to bud blight, bacterial wilt, leaf spot, rust and mildew. Aphids and mites are occasional visitors.

Garden Uses

Mass or group in the mixed shrub border or open woodland garden. Also effective as a lawn specimen, accent or hedge. Provides late summer bloom when few other shrubs are in flower.