Easily grown in average, medium moisture, well-drained soils in full sun. Intolerant of shade. Prefers deep, continually moist, fertile soils, but seems to tolerate a wide variety of soils. Avoid alkaline soils however. Trees are not reliably winter hardy in the northern areas of USDA Zone 6, including St. Louis.
Formosa sweet gum is a low-maintenance deciduous shade tree that is native to southern China and Taiwan. It typically matures to 40-60’ (less frequently to 120’) tall with a straight trunk. Habit is pyramidal in youth, but trees usually develop oval-rounded crowns with age. Glossy, long-stalked, deep green leaves (3-6” across) have three-five lobes with the middle lobe being triangular. Leaves have acuminate tips, serrate margins and cordate to truncate bases. Young leaves are tinted with lavender. Fall color is variable, ranging from showy reds and yellows to mediocre greens. Non-showy, monoecious, yellow-green flowers appear in spherical clusters in April-May. Female flowers give way to gum balls which are spherical spiny fruiting clusters to 1.5” diameter. Gum balls mature to dark brown and usually remain on the tree through the winter, but they do create clean-up problems (remove litter and protect walking areas) during the general period of December through April as the clusters fall to the ground. On the positive side, the gum balls of this species are less of a safety threat to humans (e.g., turning an ankle by inadvertently stepping on a cluster) than the gum balls of the native U. S. species (see Liquidambar styraciflua) because they are softer and less woody than those of the U. S. species. The common name of sweet gum refers to an aromatic sweet balsam or gum that exudes from wounds to the tree. In further reference to the color of this gum, the genus name basically means liquid amber.
No serious insect or disease problems. Webworms, bagworms, caterpillars, leaf miners, borers and scale may cause problems in some areas. Canker and bleeding necrosis can be significant problems. Leaf spots and wood rot may also occur. Iron chlorosis will develop in alkaline soils.
Excellent shade, lawn or park tree. Must be planted in large area with room to grow. Street tree use may be limited by concerns over fruit litter problems and roots causing damage to sidewalks. Tree wood has been widely used for a number of applications including flooring, furniture and home interiors.