Liquidambar styraciflua, more commonly called sweetgum, is a beautiful ornamental shade tree, turning traffic-stopping shades of bright red and orange in autumn. It is best known, however, for the huge number of brown, hard, spiny seedpods it drops in the fall and winter. Not only do these seedpods make a prickly mess under the tree, but they are very painful if stepped on, can damage a lawnmower, or scratch paint on a car. The pods have earned the sweetgum many nicknames, including sticky ball tree, gumball tree or monkey ball.
The American sweetgum tree reaches 60 to 70 feet at full maturity, with a 45-foot spread. It grows in an oval, somewhat pyramidal shape. The star-shaped, glossy green leaves have a pleasant smell if crushed. The sweetgum is spectacular in autumn, with leaves turning orange and flame-red before falling. Yellowish-green flowers develop in late spring and are not particularly showy. The distinctive sticky ball seedpods start off green, turning hard and brown before dropping off the tree through fall and winter.
The sweetgum is hardy through USDA zones 5 to 9. It grows best in full sun, although it can tolerate filtered shade. It prefers moist, well-drained soil. It grows quickly and is usually quite hardy. If allowed to fruit, you will need to spend considerable time raking up the spiny seedpods, which will blanket the ground; if stepped on barefoot, they can cause a painful wound.
Furniture, trim, veneer and cabinets are made from sweetgum's reddish brown heartwood, and its pulp is used to make paper. According to Floridata, the wood sometimes is sold as Italian mahogany or satin walnut. The sap can even be used to flavour chewing gum. Despite the annoying seedpods, sweetgum is widely planted as an ornamental shade tree, prized for its outstanding fall colour. The seedpods attract many birds and small animals, and are a particular favourite of yellow-bellied sapsuckers.
Seed Ball Prevention
According to West Virginia University, a trademarked spray called Florel Fruit Eliminator, distributed by the Monterey Chemical Company, prevents the development of the sweetgum's seedpods. Apply the spray when the tree has produced flowers, but before they start to develop into seedpods. If you spray the tree thoroughly during the brief window between flowering and pod production, the spray is effective in preventing fruit production. You can find Florel Fruit Eliminator at garden centres or nurseries.