Liquidambar styraciflua
American Sweetgum
Mature Size, Growth, Longevity
Usually gets 60-75' tall & 40-70' wide, but in the wild, to 120-160' tall by 80-90' wide. Pyramidal habit of youth becomes oblong/rounded w/ age. Medium growth rate on dry sites; fast rate if moist. Long-lived, to 150-300 yrs.
Native Range
Kentucky Native — Native trees occur on river bottoms, on deep, rich, moist, alluvial soils, as well as on a variety of other sites, in Connecticut, south to New York, to Florida, southern Ohio, Indiana, Illinois, Missouri to Texas & Mexico. Native throughout Kentucky.
Flower and Fruit Details
Flowers small, yellow-green, monoecious, w/ female flowers a 1/2" rounded head on slender stalk; male in a 3-4" panicle, April-May, as leaves are emerging. Not showy. The spiny, aggregate fruits, sometimes called "gum balls", are a mace-like syncarp of dehiscent capsules, 1-1.5" diameter, brown, winged seeds inside, persisting into winter, dropping sporadically, often causing a litter problem.
Leaf and Bark Features
Deciduous: 4" to 7.5" alternate, simple, star-shaped leaves, w/ 5-7 pointed lobes, dark glossy green on top, lighter beneath, w/ some axillary tufts of pubescence on major veins. Excellent fall color: yellow/purple/red. Petiole: 2.5-4" long. Leaves persist late into fall. Young stems shiny brown, aromatic when scratched; may develop corky wings w/ age. Solid, star-shaped pith. Bark on older trunks is silvery-gray/grayish brown, deeply furrowed into narrow, rounded ridges.
Culture and Care
Transplant in March. Best in deep, moist, slightly acid soils (pH 6.1-6.5) in full sun. Tolerates poor drainage. Zone 5-9. Needs a larger space in the landscape for roots to develop. Not good for city plantings or small spaces. Not pollution tolerant. Tolerates clay/flooding/soil compaction. Avoid shade. Few insect and disease problems. Iron chlorosis in high pH soils.
Strengths, Weaknesses, Other Facts
Strong branches. Wind-firm. 3-season interest: Spring, summer & fall. Goldfinches & other songbirds enjoy the seeds within the fruit capsule in the fall & winter. Genus name means "liquid amber" (fragrant resin). Common name refers to the aromatic sweet balsam or gum that exudes from wounds to the tree.
Suggested Uses
Excellent lawn, park or street tree, but needs a large area for root development as they will lift sidewalks and can interfere w/ mowing.
Taxa and Plants of this Species at BCA
The following taxa are (or were) represented in the collections at Boone County Arboretum. Additional taxa may be available in the trade that are not included here.
Liquidambar styraciflua 'Moraine' // Moraine Sweet Gum
Tree. This is the most cold-hardy American Sweetgum cultivar, surviving -20 to -25 degrees F. Excellent, bright red/scarlet fall color, sometimes mixed w/ purple, yellow or orange. Maintains its pyramidal, upright-oval shape throughout its lifetime. Very uniform habit and faster growing than the species. Leaves are dark, glossy green in the summer. Size: 40-60' tall and 25-40' wide. Branches often develop corky ridges or wings. Develops a straight, single leader. Bark becomes deeply ridged at about 25 years of age. Good tree for large parking lot islands, wide tree lawns, buffer strips around parking lots, home landscapes, golf courses and parks. Does produce some fruit, but less than the species.
BT001679Liquidambar styraciflua 'Rotundiloba' // Roundleaf Sweetgum
Tree. The 5-7 leaf lobes are rounded, like the tips of one's fingers, rather than the typical pointed star-shaped leaf of the species. Individual branches of this chimera occasionally revert back to pointed lobes. Normally, does not produce any fruit. Grows fast in any soil. Average mature size 50-70' tall and 40-50' wide. Growth habit is more narrow-pyramidal/open-erect-upright than the species. Fall color may vary from year to year from rich reddish-purple/dark burgundy to yellow/orange. Zone 6(5)-9. Has survived to at least -10, and one source says to minus 24 degrees in the Louisville, KY area. Previously listed by some sources as 'Obtusiloba', but that is incorrect.
BT003850 - BT005025Liquidambar styraciflua 'Silver King' // Silver King Sweetgum
Tree. The green/blue-green leaves of spring & summer are variegated, w/ beautiful, bold, wide, creamy-white to silvery-white margins. Pinkish-rose/crimson to rich purple-red fall color, w/ multiple colors per leaf. Average mature size 40-65' tall & 25-45' wide. Moderate rate of growth; slower growing than most sweetgum cultivars, due to the variegated leaves with less chlorophyll. Does well in full sun; tolerates light shade. Upright-pyramidal to oval habit. Resistant to Verticillium wilt fungus disease.
BT007390Liquidambar styraciflua 'Slender Silhouette' // Slender Silhouette Sweetgum
Tree. Amazingly narrow, upright-columnar-conical to fastigiate form, growing straight up, like a totem pole of lustrous, dark green foliage, to 50-70' tall and only 3-8' wide. Leaves turn yellow, orange, red and burgundy colors in the fall. Respected plantsman and author, Dr. Michael Dirr, calls this "one of the best upright trees that has been introduced in recent years." Introduced by nurseryman, Don Shadow, who found it growing wild near a railroad track. Full sun to light shade. A tall, thin tree, perfect for tight spaces, small gardens, or as a vertical accent plant. Seemingly fruitless at first, it eventually produces a few fruits, and occasionally yields a heavy crop of "gumball" fruits. Bark becomes deeply furrowed with age.
BT007230 - BT007240 - BT007250