Ailanthus altissima (Mill.) Swingle
Tree of Heaven| Threat Level | Category |
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| Established | Tree |
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Similar Species May be confused with the following native and/or non-native species. Landscape Alternatives lists native horticultural substitutes |
Juglans spp. Rhus spp. Landscape Alternatives |
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Description
Height
Ailanthus can grow rapidly to 80-100 feet (25-30 m) and 6 feet (1.8 m) diameter.Leaves
Deciduous leaves are typically odd-pinnately compound with 11-41 leaflets, may be even-pinnate, on light green to reddish green stems 1-3 feet (30-90 cm) long. Leaflets are dark green above with light green veins and undersides and are not always directly opposite each other. Shape is lanceolate and asymmetric with long tapering tips and smooth edges except for 1-5 teeth at the base. Each leaflet has one or more prominent dark green circular glands (round dots) on the underside near a tooth apex. Both leaflet surfaces have minute hairs and glands. Leaflets are each 3-5 inches (7.5-12.5 cm) long and 1-2 inches (2.5-13.0 cm) wide. Crushed foliage has an acrid odor. Leaf scars are large and triangular with numerous bundle scars. Crushed twigs or leaves and pulled seedlings produce a foul odor.Twigs
Light brown to reddish brown twigs are very stout and covered with fine hairs when young. Twigs are light colored lenticles (dots) and heart-shaped leaf scars. Pith is continuous and yellowish in color. Buds are finely hairy, dome-shaped, relatively small and solitary, partially hidden by the leaf base. Terminal buds are absent. Branches are light to dark gray, smooth and glossy.Bark
The smooth, striped, gray-brown or light brown bark cracks with age and exhibits light-colored grooves.Flowers
Male and female flowers are 0.25 inch (0.5 cm) long and form large, light green terminal panicles. Each flower is radially symmetrical with 5 or 6 petals. Some trees may have both male and female flowers, but most individuals are unisexual. Male flowers have a foul scent. Each tree may produce up to several hundred inflorescences a year. Blooms late May through early June.Fruit
Produced on female trees, fruit is 1.0-1.5 inch (3-8 cm) long, dry, and segmented splitting into 2-5 winged sections, each containing a single seed. Each winged seed has a twisted tip.Seeds mature in late summer or early fall and form dense, showy pink to russet to tan clusters that persist through the winter. Each cluster may contain hundreds of seeds.Images
Photo: James H. Miller, USDA Forest Service, Bugwood.org.More images of Ailanthus altissima
Life History
Ailanthus, also known as tree-of-heaven or Chinese sumac, is a persistent and aggressive weed throughout much of Europe and North America. It belongs to the Simaroubaceae (Quassia) family, which is primarily tropical or subtropical. Ailanthus grows quickly and can reach a height of 8 feet (2.5 m) in its first year. Seedlings can grow 3-6 feet (1-2 m) the first year, and root sprouts have been found to grow 10-14 feet (3-4 m) the first year. Vigorous growth can continue for four years or more.Ailanthus reproduces from both prolific wind- and water-dispersed seeds and root sprouts, colonizing to form thickets and dense stands. Seeds are easily windblown and a high percentage are viable. True seedlings are smaller and thinner-stemmed than root sprouts and have trifoliate leaves. Sprouts will have a cluster of leaves with variable numbers of leaflets. When pulled from the ground, seedlings will reveal thin, branching roots while sprouts will be firmly connected to a thick, rope-like root. Sprouts may emerge up to 50 feet (15 m) from the nearest existing stem. Most stems begin to reproduce at 10-20 years, though two-year old sprouts can produce fruit, and first-year seedlings have been observed flowering. Ailanthus is intolerant of shade and floods; in natural stands reproduction is primarily by sprouting. The trees are typically short-lived (30-50 years), though some have survived for over 150 years.
Habitat
Ailanthus is adapted to a wide variety of soil conditions. It tolerates drought and rocky conditions to the extent of growing out of pavement cracks. The tree is common in urban areas and disturbed sites throughout its range, and it is a pioneer in succession with limited ability to compete in a closed-canopy forest. It can, however, take advantage of forests defoliated by insects (e.g., gypsy moth) or impacted by slides, windstorms, or other natural disasters. Ailanthus forms dense, clonal thickets that displace native species. A few trees along a fencerow or forest edge can rapidly invade adjacent meadows. In addition to its prolific vegetative reproduction, Ailanthus has allelopathic effects on many other tree species and may consequently inhibit succession.Origin and Distribution
Ailanthus, native to China, was introduced to Europe and then to the United States in the late eighteenth century. An early Chinese saying refers to spoiled children as "good for nothing ailanthus sprouts." It was, nevertheless, widely planted in Europe and North America until recently. Botanists in the late 1800s noted that it was wide-spread and naturalized in Tennessee. Other states were it is considered invasive: AZ, CA, CT, DC, DE, FL, HI, IN, KY, LA, MA, MD, MI, MO, NC, NH, NJ, NM, NY, OH, OK, OR, PA, RI, SC, VA, WA, WI, WV. Federal or state listed as noxious weed, prohibited, invasive or banned in CT, MA, NH, VT.Sources: Information on this plant page is derived from the Tennessee Management Manual and James H. Miller's Nonnative Invasive Plants of Southern Forests, USDA Forest Service.
Management Recommendations
Mechanical Controls
Cutting: Cut trees at ground level with power or manual saws. Cutting is most effective when trees have begun to flower to prevent seed production. Because Ailanthus spreads by suckering, resprouts are common after treatment. Cutting is an initial control measure, and success will require either an herbicidal control or repeated cutting for resprouts.Girdling: Use this method on large trees where the use of herbicides is not practical. Using a hand axe, make a cut through the bark encircling the base of the tree, approximately 15 cm (6 in) above the ground. Be sure that the cut goes well into the cambium layer. This method will kill the top of the tree but resprouts are common, and may require follow-up treatments for several years until roots are exhausted.
Hand Pulling: Ailanthus is effectively controlled by manual removal of young seedlings. Plants should be pulled as soon as they are large enough to grasp, but before they produce seeds. Seedlings are best pulled after a rain when the soil is loose. The entire root must be removed since broken fragments may resprout.
Herbicidal Controls
Foliar Spray Method
This method should be considered for large thickets of Ailanthus seedlings where risk to non-target species is minimal. Air temperature should be above 65 °F to ensure absorption of herbicides.Glyphosate: Apply a 2% solution of glyphosate and water plus a 0.5% non-ionic surfactant to thoroughly wet all leaves. Use a low pressure and coarse spray pattern to reduce spray drift damage to non-target species. Glyphosate is a non-selective systemic herbicide that may kill non-target partially-sprayed plants.
Triclopyr: Apply a 2% solution of triclopyr and water plus a 0.5% non-ionic thoroughly wetting all leaves. Use a low pressure and coarse spray pattern to reduce spray drift damage to non-target species. Triclopyr is a selective herbicide for broadleaf species. In areas where desirable grasses are growing under or around ailanthus, triclopyr can be used without non-target damage.
Cut Stump Method
This control method should be considered when treating large individual trees or where the presence of desirable species preclude foliar application. Stump treatments can be used as long as the ground is not frozen.Glyphosate: Horizontally cut stems at or near ground level. Immediately apply a 50% solution of glyphosate and water to the cut stump making sure to cover the outer 20% of the stump.
Triclopyr: Horizontally cut stems at or near ground level. Immediately apply a 50% solution of triclopyr and water to the cut stump making sure to cover the outer 20% of the stump.