A common deciduous tree in the United States is the American sweetgum. Distinguishing characteristics are the spiky fruits and the star-shaped leaves that put on a show in the fall.
This is not related to the eucalyptus trees, which are sometimes called gum trees. It is also not related to the black gum (Nyssa sylvatica).
- Latin Name: The Latin name for this tree species is Liquidambar styraciflua. It is a member of the Altingiaceae family and is sometimes classified in the Hamamelidaceae (Witch hazel) family.
- Common Names: This tree has many common names and may be known as sweetgum, gumtree, red gum, star-leaved gum, American sweetgum, alligator-wood, bilsted, satin-walnut, American-storax, liquid amber
- Preferred USDA Hardiness Zones: If you live in Zones 6-10, this could be the tree for you. It originally comes from the eastern United States.
- Size & Shape of American Sweetgum: When it is young, the American sweetgum grows in a pyramidal shape. As time goes on, it may change to a round or oval shape.
- Exposure: You should choose a location with full or part sun.
Foliage, Flowers, and Fruit
The leaves form in a distinct star shape with 5-7 lobes. In the fall, they change late in the season and provide a brilliant show in shades of red, orange, purple, gold, yellow and green.
The flowers aren't much to behold. They do come out in April and May, but the blooms are green, and you will probably miss them among the green leaves. There are both male and female flowers on the same tree, making this a monoecious species.
Many people are familiar with the spiky ball-shaped fruits, which are woody capsules. At first, they are green, then they turn brown as the season progresses. They are often considered to be a nuisance, so that should be considered before you plant it.
Never fear — if you aren't in the mood to battle with the fruits in your yard, there is a non-fruitful variety available. Look for 'Rotundiloba' at your local nursery.
Don't put one of these near areas with concrete like patios, curbs or sidewalks. The roots grow near the surface and may start breaking these places apart.
The soil should be neutral or acidic, as alkaline soils may cause the tree to become chlorotic. You can make your soil more acidic if needed.
There are several ways to propagate American sweetgum. You have the choice of planting seeds, making cuttings and rooting them, or you can even graft or bud them onto a budstock.
Planting is best done in the spring as opposed to autumn.
Maintenance and Pruning
You may want to rake up the fruit before you mow your lawn. The balls may go flying when the blades hit them or dull the mower.
You can prune after the flowers come in April and May if you need to take care of any dead, diseased or damaged branches. There isn't usually much of a need otherwise.
Pests & Diseases
You may see these pests on your tree:
- Bagworms (members of the Psychidae family)
- Black vine weevil (Otiorhynchus sulcatus)
- Calico scale (Cottony-cushion scale (Icerya purchasi)
- Fall webworm (Hyphantria cunea)
- Fruittree leafroller (Archips argyrospila)
- Giant whitefly (Aleurodicus dugesii)
- Leaf miners (belongs to many genera)
- Redhumped caterpillar (Schizura concinna)
- Sweetgum scale (Diaspidiotus liquidambaris)
- Tent caterpillars (found in the Malacosoma genus)
- Tussock moths (those in the Lymantriidae family)
- Walnut scale (Quadraspidiotus juglansregiae)
- Bacterial leaf scorch
- Cankers (caused by bacteria and fungi)
- Iron chlorosis (in alkaline soils)
- Leaf spots (brought on by fungi and bacteria
- Leader dieback (a result of environment or injuries)