Trident maple (Acer buergerianum) leaves are glossy green and shaped like a duck's foot with three pointy lobes. In autumn the foliage turns a rich yellow and then deep russet red. This small ornamental deciduous tree also displays an exfoliating bark with plates and scales of brown, tan, orange and gray. Often grown as a small-size shade or street tree or bonsai specimen, it is appropriate in U.S. Department of Agriculture hardiness zones 5 through 8, and to zone 9 in the Mediterranean climate of the West Coast.
Growing between 5 to 10 inches each year, trident maple matures 25 to 40 feet tall and 15 to 25 feet wide. The University of Connecticut comments that it typically grows 20 to 25 feet tall, but ideal growing conditions readily allow the plant to reach slightly larger sizes.
The trident maple's canopy is rounded and spreading. Although a singular plant, it tends to branch very low on its trunk, often creating a multi-trunked appearance. "Sunset Western Garden Book" recommends pruning off lowest branches when the tree is young to create a structure that allows for access under the tree, especially if near a sidewalk or street.
Newly emerging foliage typically has a reddish or bronze hue but matures to a rich, shiny Kelly green by late spring. The non-showy flowers appear at the same time the leaves emerge, and result in small green samara seeds. The youngest twigs have a slight red-brown cast to them, while older sections of branches are much more gray-brown.
Garden literature often cites trident maple as being drought tolerant. While it does handle slight to moderate bouts with dry soil, its growth is retarded by overly dry conditions. According to Dr. Michael Dirr, trident maple's leaves do not develop leaf scorch or brown leaf margins when stressed by drought, unlike most other species of maple. This masks the effects of drought. Overall, trident maple grows best in a slightly acidic soil that is moist and well-drained, although it does tolerate infertile and slightly alkaline soils, too. Moreover, the tree also demonstrates good overall resilience to winter cold and summer heat.
The University of Connecticut reports that trident maple trees survive winter cold much better when mature; younger saplings and trees tend to suffer twig dieback in cold winters. Less winter kill is experienced in the warmer parts of USDA hardiness zone 5, where temperatures don't drop below minus 15 F in winter. The Missouri Botanical Garden mentions that in regions where ice storms or heavy snows are common, trident maple suffers limb breakage.