American Sweet Gum
American Sweet Gum
Zone: USDA Zones 5-9
Leaves in general
Additional facts on Americian Sweet
Liquidambar styraciflua L.
Sweetgum, American sweetgum
Hamamelidaceae (Witch-Hazel Family)
USDA Symbol: list2
USDA Native Status: Native to U.S.
A large, open-crowned tree, sweet-gum grows 75 ft. tall in cultivation and up to 130 ft. in the wild. Large, aromatic tree with straight trunk and conical crown that becomes round and spreading. Young trees are distinctly conical in form. The long, straight trunk is occasionally buttressed and bears strong, ascending branches. Glossy green, deciduous leaves have five deep lobes making a star shape. Fall foliage is purple and red, and will become colorful even without cold temperatures. The fruit is a globular, horny, woody ball, 1 in. in diameter, which hangs on a long stem and persists through January.
An important timber tree, Sweetgum is second in production only to oaks among
hardwoods. It is a leading furniture wood, used for cabinetwork, veneer,
plywood, pulpwood, barrels, and boxes. In pioneer days, a gum was obtained from
the trunks by peeling the bark and scraping off the resinlike solid. This gum
was used medicinally as well as for chewing gum.Commercial storax, a fragrant
resin used in perfumes and medicines, is from the related Oriental Sweetgum
(Liquidambar orientalis Mill.) of western Asia.
* cold hardy to zone 5
* native to Eastern United States, from Southwestern Connecticut to Florida
* also found in Mountains of Mexico and Guatemala
Habit and Form
* deciduous shade tree
* typically 60 to 80' tall and 40 to 60' wide
* can easily exceed 100' tall
* Pyramidal when young, oblong to rounded when mature
* usually maintains a single leader
* medium to fast grower
* 1 to 1.5" spiny balls; change from green to brown
* look like a mace weapon
* become noticeable in the late summer and fall
* persist in winter
* chlorosis on high pH soils
* lack of cold hardiness, especially young trees
* because of wide geographical range it is important to use northern seed sources for trees in New England or the Northeast
* has a shallow root system
* spiny fruit balls can be a litter problem
'Grazam' (Grandmaster™) - This new pyramidal selection grows 50' tall and wide with glossy green leaves that turn shades of red-purple and orange in fall.
'Gumball' and 'Oconee' - These cultivars are both notable for their dwarf, multi-stemmed shrubby habit to 15' tall with a smaller spread. They exhibit good fall color, with 'Oconee' expressing better cold-hardiness.
'Moraine' - Probably the most common cultivar in the industry, this plant has a uniform upright rounded habit. It is faster growing and more hardy than other forms, plus it features good red fall color.
'Rotundiloba' -This is an interesting form whose leaves have rounded lobes. It appears to set fruit rarely or never. The degree of fall color varies widely each year; in addition the tree can develop narrow branch crotch angles and a more open habit. It is probably only cold hardy to -10, but a tree in Storrs, CT has survived several winters without injury. Due to its non-fruiting habit, it may be a viable choice for warmer zones.
"Shadow Columnar Form" - An as yet unnamed selection with a remarkable fastigiate, columnar habit. Woody plant expert Michael Dirr feels this plant has great commercial potential.
'Variegata' (may be the same as 'Aurea' and 'Goduzam' (Gold Dust™))- One of the finest variegated, hardy shade trees, this plant is a strong grower to 60' tall with a narrower spread. The leaves are mottled with cream areas that intensify as the season progresses. The habit is oval-rounded and the plant exhibits good cold-hardiness. Other variegated forms include 'Silver King' and 'Golden Treasure', with margined leaves.
'Burgundy' – dark red to purple fall colors may persist
'Clydesform' - sold as Emerald Sentinel; columnar or narrowly pyramidal; slow growth to 9 meters; yellow-orange fall colors.
'Festival' – columnar; pale green summer leaves; bright fall hues of yellow, pink and red; less hardy than most.
'Goduzam' (Gold Dust) – variegated; pink to red-purple in fall.
'Palo Alto' – various shades of red in fall; best in California.
'Parasol' – develops rounded crown; mature height 10 meters; deep red fall color.
'Slender Silhouette' - very narrow columnar form.
'Worplesdon' – cutleaf cultivar with orange, red and purple fall colors.
Diseases and insects
The four most common decay organisms reported were Fomes geotropus, Pleurotus ostreatus, Lentinus trigrinus, and Ganoderma lucidum.
Other diseases of sweetgum that may be important occasionally are an abiotic
leader dieback or blight, twig canker, and trunk lesion caused by Botryosphaeria
ribis, and bleeding necrosis, which may be a combination of sweetgum blight and
B. ribis trunk lesion. Of these, only sweetgum blight is widely distributed and
has caused heavy mortality in several States. It has received intensive study in
Maryland and Mississippi. Drought appears to be the primary cause. In the lower
Mississippi River flood plain, blight severity was found to be correlated with
soil properties affecting moisture supply. Severity of dieback was reduced by 68
percent in 2 years by irrigating when soil moisture dropped below 40 percent of
field capacity. There is a good possibility that sweetgum blight is most common
in stands of root sprout origin. In the Georgia Piedmont and Coastal Plain of
South Carolina, many groups of trees are composed of stems that are of root
sprout origin and depend on a single root system complex for water uptake.
During prolonged droughts such as occurred in the 1950's, this limited root
system may not be adequate to satisfy the water requirements of the sprout
complex, and many of the stressed trees may suffer blight.
Except for leaffeeders, insects usually attack only trees that are already damaged, decadent, or dead. These include the bark beetles (Dryocoetes betulae and Pityophthorus liquidambarus), the ambrosia beetles, which include Platypus compositus, and the darkling beetles (Strongylium spp.). The leaffeeders include the forest tent caterpillar (Malacosoma disstria) and the luna moth (Actias luna). In addition, a treehopper (Strictocephala militaris) is known to spend its entire life cycle on sweetgum in northeast Georgia but is not considered to be harmful .
Sweetgum is used principally for lumber, veneer, plywood, slack cooperage, railroad ties, fuel, and pulpwood. The lumber is made into boxes and crates, furniture, radio-, television-, and phonograph cabinets, interior trim, and millwork. The veneer and plywood are used for boxes, pallets, crates, baskets, and interior woodwork .
No hybrids of sweetgum are known to exist. There is considerable evidence, however, that differences between ecotypes, such as swamps and uplands, should play an important role in selection of mother trees for artificial regeneration programs .
The earliest record of the tree appears to be in a Spanish work by F. Hernandez, published in 1651, in which he describes it as a large tree producing a fragrant gum resembling liquid amber, whence the name. In Ray's Historia Plantarum (1686) it is called Styrax liquida. It was introduced into Europe in 1681 by John Banister, the missionary collector sent out by Bishop Compton, who planted it in the palace gardens at Fulham.
Sweetgum is one of the most common southern hardwoods. It occurs in the United States from southern New York west to southern Missouri and east Texas and south to central Florida, and in Mexico from southern Nuevo León south to Chiapas, as well as in Guatemala and El Salvador. In the United States it occurs at low-to-moderate altitudes, while in Mexico, Guatemala, and El Salvador it grows at higher altitudes in mountains where the climate is more temperate.
As well as in its native area, it has been introduced to many parts of the world, including Argentina, Australia (as far north as Brisbane), Brazil, Chile, Europe, Hawaii, Namibia, New Zealand, South Africa, Uruguay and Zimbabwe. In the United States, it is especially popular in California, where it has escaped from cultivation, and is commonly known as "liquid amber". In Florida, it is sold at least as far south as Lake Worth. In Canada, it is commonly cultivated in cities of western British Columbia such as Victoria and Vancouver. It also grows well at Toronto and Niagara Falls. Farther east, it grows as a root-hardy shrub in Ottawa and Montreal. It also grows well in New England including the states of Rhode Island, Massachusetts, Connecticut and Southeast New Hampshire. It is also cultivated in the Chicago area near the warmer microclimate around southern Lake Michigan. It grows best in moist, acidic loam or clay soil, and tolerates poor drainage. Salt tolerance is moderate. Chlorosis can develop on alkaline soil, especially where organic matter is low.