Culture
Cool, moist, acidic, well-drained soils in full sun to part-shade. Winter hardy to USDA Zone 7 (maybe 6b). If planted in the ground in St. Louis (Zone 6a), it should be sited in a protected location sheltered from strong winds and given a good root mulch.
Noteworthy Characteristics
Acer pentaphyllum, commonly called Chinese maple or five-lobe maple, is a small, vase-shaped, multi-stemmed, deciduous tree that typically matures over time to 20-30’ tall with a slightly narrower spread, but often grows much shorter as a shrub to 9-12’ tall. It is native to mixed forests and valleys in several hidden locations in a remote part of China located in southwestern Sichuan Province. This is an endangered species on the brink of extinction in the wild. Known populations at this time total fewer than 200 plants. Experts believe that survival is threatened by a combination of factors including habitat loss, animal grazing, harvest of woody fuel by local farmers, and fragmentation. This tree is andromonoecious (staminate and perfect flowers on the same tree). Small yellowish flowers (each having 5 petals, 8 stamens and glabrous filaments) bloom in late spring each year. Flowers are followed by fruits (samaras), with wing and nutlets to 1” long and wings spreading to 90 degrees. Opposite, palmately-compound, red-petioled, dark green leaves (each to 3” long) emerge late in spring each year. Each leaf has 5 (occasionally 7) very narrow, acuminate-tipped leaflets (to 3-4” long and 1/2” to 3/4” wide) which are divided to the petiole. Fall color ranges from yellow to orange to red. Unusual leaves more closely resemble the leaves of marijuana than of maple, thus leading to the sometimes used common name of marijuana maple for this tree.
This maple was discovered in southwestern Sichuan near the small Tibetan town of Muli by plant collector Joseph Rock on an expedition sponsored by the National Geographic Society in 1929. Three trees survived Rock’s journey, all ending up at the Strybing Arboretum in San Francisco. These trees all died by 1991, but were propagated by grafting prior to death.
Genus name is the Latin name for a maple tree.
Specific epithet comes from the Greek words penta meaning five and phyllon meaning leaf in reference to the five lobed leaves.
Problems
No serious insect or disease problems. Potential disease problems include verticillium wilt, leaf spots, tar spot, canker and root rots. Potential insect problems include aphids, scale, borers and caterpillars. Mites may appear.
Uses
May be very difficult to locate in commerce. Specimen. Small landscapes. Woodland garden margins. Large containers.