Hydrangea quercifolia (Oakleaf Hydrangea)

Hydrangea quercifolia, the oakleaf hydrangea, is a notable exception to the appearance, growth habit, and cultural requirements of mophead and peegee hydrangeas. The latter two types are mostly suited to climates with humid air and summer rains. 

Stunning Garden Specimen

In Sonoma County, Master Gardeners recommend only one hydrangea as a suitable garden choice, Hydrangea quercifolia, the oakleaf hydrangea.  

• Oakleaf hydrangea is the single species on our list of Recommended Plants for Sonoma County. It not only thrives in our climate but is a stunning garden specimen.
• The normal size is about 6 ft. high, arching to 8 ft. wide in a loose, pleasing mounding habit loved for showy, late spring to early summer white flowers and fall foliage color ranging from red to purple to bronze. 
• Deep green leaves are thick, coarse, and lobed, similar to some oak species. Leaf undersides are bristled with tiny hairs that aid in the plant’s moisture retention. Only low-water is needed in dry summers, more in sun than in shade. 
• Named varieties differ in flower size and shape.
  • Those that produce larger plants up to 15 ft. wide should be chosen with care.
  • ‘Snowflake’ and ‘Snow Queen’ are popular choices, although their flower clusters are a bit heavy.
  • ‘Alice’ has exceptionally large, long-lasting flowers and foliage that ages to burnished red and purple.
  • ‘Pee Wee’ and ‘Sikes Dwarf’ are recommended for smaller gardens, as they are in the 4-6 ft. range. 
  • ‘Munchkin’ stays at 3 ft. high and wide.

How to Grow

Oakleaf hydrangea is generally considered a shade-loving shrub with large, dramatic, pyramidal blooms that may reach 12 in. long.

• It can grow, however, in a range of exposures from full sun to full shade; dappled shade is ideal. 
• Inland, plants require more shade; closer to the coast, the more sun they tolerate.
• Rich, well-drained soil amended with compost produces the most beautiful shrubs. In any garden, allow ample space for normal size to develop.
• In very large gardens, several shrubs can be planted spaced at a distance from one another to create a dynamic, arching mass of flowers and foliage.
• Hydrangea quercifolia has no known disease or pest problems but, like other hydrangeas, all parts are slightly toxic if ingested.

Pruning

Prune oakleaf hydrangea after bloom to stimulate new growth and control size. When not pruned, stems continue to elongate, bloom in successive seasons, and grow to a larger size.

• Make cuts below faded blossoms and just above a pair of buds lower on the stems. Next year’s flowers will appear at branch tips of new growth from these buds.
• As shrubs mature, cut a few oldest stems to the ground, removing any that are damaged or crowded.
• Allow shrubs to spread into a broad clump or remove new stems to limit size.
• Spring growth from the ground up will not produce flowers the first year, only foliage.
• Leaves may persist into early winter before dropping to reveal cinnamon-colored, peeling branches.

August 2023