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.
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.
'Interhydia', commonly sold under the trade name of PINK DIAMOND, is a compact cultivar that typically grows in a rounded, upright form to 5-10’ tall and as wide. It was developed in the 1980s as a seedling of Hydrangea paniculata 'Unique'. It is noted for producing dense, pyramidal, cone-shaped panicles (to 12” long and 8" across) of sterile and fertile flowers at the ends of red-stemmed branches. Flowers emerge white but mature to a rich pink. The smaller fertile flowers are somewhat hidden beneath the showier, sterile ones. Strong stiff stems hold the flower panicles upright with no drooping. Flowers bloom from July through September. Elliptic to ovate, serrate, dark green leaves (to 6” 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 will persist well into winter.
No serious insect or disease problems. Some susceptibility to bud blight, bacterial wilt, leaf spot, rust and mildew. Aphids and mites are occasional visitors.
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.