Plant of the Week 05/30/2005: Oakleaf Hydrangea (Hydrangea quercifolia)

Plant of the Week 05/30/2005

Oakleaf Hydrangea (Hydrangea quercifolia)

Hydrangea quercifolia W. Bartram

Photographed by: Chelsie Vandaveer
Credits: Oakleaf hydrangea photographed in Chelsie's garden.
Other Information: Olympus C-8080wz

In the summer of 1776, the fourth year of his exploration of the southeast U.S., William Bartram ventured from the Ocmulgee in Georgia where "on the East bank of the river lie the famous Oakmulge fields, where are yet conspicuous very wonderful remains of the power and grandeur of the ancients of this part of America, in the ruins of a capital town and settlement...."

After two days travel, Bartram and company "...encamped close by a beautiful large brook called Sweet Water, the glittering waving flood passing along actively over a bed of pebbles and gravel....

"I observed here a very singular and beautiful shrub, which I suppose is a species of Hydrangia [sic]. It grows in coppices or clumps near or on the banks of rivers and creeks; many stems usually arise from a root, spreading itself greatly on all sides....these branches are crooked...and divide, forming others which terminate with large heavy panicles or thyrsi of flowers...the leaves which clothe the plants are very large, pinnatifid or palmated, and serrated or toothed, very much resembling the leaves of some of our Oaks...and are of a fine, full green color." (Travels of William Bartram)

The graybeard or oakleaf hydrangea (Hydrangea quercifolia) is one of two species native to the southeast U.S. Unlike most Hydrangea with flattened 'lacecaps' or rounded 'mopheads' (corymbs) of flowers, the oakleaf has conical panicles. The tips of each branch of the panicle have a sterile flower: actually four or five showy sepals. Hidden behind the attractive 'sepal flowers' are numerous fertile flowers. They appear like fringe along the branches of the panicles.

In colder parts of the oakleaf's range the leaves turn red and orange before falling. The 'sepal flowers' remain on the panicles turning pinkish before fading to silvery brown—graybeards. If winter winds are mild, the graybeards will remain through to spring. The oakleaf blooms on new wood; any pruning should take place in the late autumn after flowering.

Linnaeus established the genus Hydrangea in 1753 with the other species native to the southeast U.S.—Hydrangea arborescens. Hydrangea refers to the fruit, a small dehiscent capsule shaped like a Greek hydria, a water-pot or ewer.

(Compiled from: Travels of William Bartram, Mark Van Doren, ed. Dover Publications, NY, 1955; A-Z Encyclopedia of Garden Plants, C. Brickell and J.D. Zuk, eds. American Horticultural Society, Dorling Kindersley, NY, 1996; Hortus Third, Staff L.H. Bailey Hortorium, NY State College of Agriculture and Life Sciences, Cornell University, Macmillan, 1976; and Taylor's Encyclopedia of Gardening, Norman Taylor, 4^th ed., Houghton Mifflin, 1961)