Also known as redgum, American storax, hazel pine, bilsted, satin-walnut, star-leaved gum, and alligatorwood, this deciduous tree is native to eastern US and Mexico where it grows in a variety of habitats including wet river bottoms and moist woodlands. It is a member of the Altingiaceae, a small plant family of one genus with 15 species. Growing from a shallow root system, the trees are up to 100′ tall, and have straight trunks with deeply ridged gray bark and sometimes corky wings on the twigs. The alternate, star-shaped leaves are 4-8″ across, palmately veined, and have 5-7 deeply separated lobes with finely serrated margins. Fragrant when bruised, the leaves are green during the growing season but turn a mixture of yellow, orange, red and purple in the fall. Inconspicuous, yellow-green, male and female flowers appear on the same tree in mid to late spring. The male flowers are in terminal racemes 2-3″ long while the female flowers are in heads in the axils of the upper leaves. The female flowers give way to pendulous, hard, spherical fruits (gum balls) that are bristly, about 1″ across and composed of 40-60 capsules containing 2 seeds. The fruits are green at first but turn brown with maturity, remain on the tree into winter and provide food for birds. In addition, the bark provides food for small mammals such as beavers, mice and rabbits. Sweet gum is valued for its timber and use as a shade tree although its roots may lift pavement and its fruit create unwanted litter. In addition, sweet gum can become invasive in favorable environments. The genus name, Liquidambar, comes from the Latin word, liquidus, meaning liquid, and the Arabic word ambar meaning amber, referring to the tree’s sap. The specific epithet, styraciflua, comes from the Greek word στύραξ (stúrax) meaning resin, and the Latin word fluere, meaning to flow, and refers to the tree’s flowing resin.
Type: Deciduous tree
Outstanding Feature: Fall coloration
Form: Pyramidal to oval
Growth Rate: Rapid
Bloom: Clusters of inconspicuous, greenish-yellow male and female flowers on the same tree in mid to late spring
Size: 60-100′ H x 40-60′ W
Light: Full sun to partial shade
Soil: Average, deep, moist, well-drained, neutral to acidic
Hardiness: Zones 5-9
Care: Plant in spring because roots need 3-4 months to become established after transplanting; clean up litter created by fruit
Pests and Diseases: Susceptible to webworms, caterpillars, borers, scale, leaf spots, wood rot, and bleeding necrosis
Propagation: Seed (1-2 months cold stratification), semi-hardwood cuttings
Outstanding Selections: Many cultivars are available that vary most significantly in intensity of autumn coloration, form, leaf-shape, plant size, and hardiness. Sterile (no gum balls), dwarf, and variegated cultivars are also available.
Photo Credit: Wikipedia