Plant of the Month – August, 2009
Photos above show the white inflorescence of Hydrangea quercifolia ‘Snowflake’ and the plant’s vivid fall color. Below: the shrub structure and an age-tinged flower cluster. Photos by Jimmy Turner.
Hydrangea quercifolia ‘Snowflake’
AT A GLANCE
Latin name: Hydrangea quercifolia ‘Snowflake’
Common name: Double-flowered oakleaf hydrangea
Plant type: Deciduous shrub
Blooming season: May until July
Flowers: Creamy white, darkening with age to pink-tinged
Foliage: Large, coarse leaves that turn red in fall
Mature height: 6 to 8 feet
Spacing: 4 to 6 feet
Hardiness: Zone 5
Exposure: Afternoon shade to full shade
Water usage: Low
Sources: Local nurseries
I consider oakleaf hydrangea an essential plant for any Texas garden. This southeastern U.S. native is much better adapted to North Central Texas than the popular mophead hydrangeas. While oakleaf hydrangeas are not usually sold as cultivated varieties, there are several improved selections available. ‘Snowflake’ is one of my favorites. This variety has double flowers that persist for a long time on the plants.
Beginning in late May, this hydrangea has large, cone-shaped inflorescences of many small flowers. They open pure snowy white, but as the flower heads age, they change from white to a pink tone. Eventually, the flowers turn light tan and last until fall. With cooler fall weather, the large, oakleaf-shaped leaves turn a magnificent burgundy. I would grow this plant for its incredible fall color even if it didn’t flower. Unlike so many other plants, the leaves stay on for several weeks before falling off.
When deciding to place this plant in your garden, be sure to leave it enough room to grow. A well-grown oakleaf hydrangea can be 8 feet tall and wide when mature. Mature plants form large, multiple-trunked specimens. I prune my plants only occasionally, to make them denser, cutting off any long stems right after flowering. This hydrangea is unparticular about soil as long as it is well-drained. Plants do suffer from iron chlorosis when planted in highly alkaline areas, so make sure to feed with a fertilizer containing micronutrients. This plant seldom has any pest or disease problems.
I like to combine the coarse texture of oakleaf hydrangeas with the soft forms of wood fern or nandina. This shrub can stand out as a single specimen plant and also works well planted in groups.
Oakleaf hydrangea is almost universally available at any retail garden center. It may take a little more looking around to find named varieties like ‘Snowflake’, but the search is worth it.
If you would like to see this plant in person, visit the Lay Ornamental Garden at the Dallas Arboretum. There are several large specimen plants along the edges of the pools. The Dallas Arboretum is located at 8525 Garland Road, overlooking White Rock Lake. For more information, visit www.dallasarboretum.org.
About the author: Jimmy Turner is the senior director of gardens at the Dallas Arboretum. Visit www.dallasplanttrials.org for more information on his trials.