Tree-of-Heaven (Ailanthus altissima)
Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.
Deciduous tree to 80 feet (25 m) in height and 6 feet (1.8 m) in diameter from a shallow root system, with long, pinnately compound leaves and circular glands under small lobes on leaflet bases. Strong unpleasant odor emitted from flowers and other parts when crushed, sometimes likened to peanuts or cashews.
Twigs stout, chestnut brown to reddish tan, smooth to velvety with light dots (lenticels) and large, heart-shaped leaf scars. Buds finely hairy, dome-shaped, and partially hidden by the leaf base. Branches light gray to dark gray, smooth and glossy, with raised dots becoming fissures with age. Bark light gray and rough with areas of light-tan fissures.
Alternate, odd- or even-pinnately compound, 10 to 41 leaflets on 1 to 3 foot (30 to 90 cm) long, light-green to reddish-green stalks with swollen bases. Leaflets lanceolate and asymmetric and not always directly opposite, each 2 to 7 inches (5 to 18 cm) long and 1 to 2 inches (2.5 to 5 cm) wide. Long tapering tips and lobed bases with 1 or more glands beneath each lobe (round dots). Margins entire. Dark green with light-green veins above and whitish green beneath. Petioles 0.2 to 0.5 inch (5 to 12 mm) long.
April to June. Large terminal clusters to 20 inches (50 cm) long of small, yellowish-green flowers, with 5 petals and 5 sepals. Male and female flowers on separate trees.
Fruit and seeds
July to February. Persistent clusters of wing-shaped fruit with twisted tips on female trees, 1 inch (2.5 cm) long. Single seed. Green turning to tan, then brown. Persist on tree for most of the winter.
Rapid growing, forming thickets and dense stands. Both shade and flood intolerant and allelopathic. Colonizes by root sprouts and spreads by prolific wind- and water-dispersed seeds. Viable seed can be produced by 2- and 3-year-old plants. A mature female tree can produce up to 300,000 wind-dispersed seeds per year that can be distributed up to 330 feet (100 m) away.
Resembles hickories (Carya spp.), butternut (Juglans cinerea L.), black walnut (J. nigra L.), and sumacs (Rhus spp.), which have pinnately compound leaves but no glands at leaflet bases. Hickories distinguished by braided bark, butternut and black walnut by their ridged mature barks, and all have large nuts. Sumacs often in a shrub shape, red or winged leaf stalks, and terminal conical flower and seed clusters.
History and use
Introduced in 1784 from Europe, although originally from Eastern China. Ornamental widely planted in cities due to pollution and drought tolerance.
Found throughout the region with dense infestations in central VA, KY, TN, NC, and SC. Scattered occurrences southward from ornamental plantings.
- Do not plant. Remove prior plantings, and control sprouts and seedlings. Bag and dispose of fruit in a dumpster or burn.
- Target female seed-producing plants.
- Minimize disturbance within miles of where this plant occurs, and anticipate wider occupation when plants are present before disturbance.
- Treat when new plants are young to prevent seed formation.
- Cutting and pulling treatments result in abundant surface root sprouts and should not be used without herbicide treatments.
- Burning treatments are suspected of having minimal topkill effect due to scant litter.
Recommended control procedures
Large trees. Make stem injections and then apply Garlon 3A when safety to surrounding vegetation is desired, or Pathway* or Arsenal AC* in dilutions and cut-spacings specified on the herbicide label (midsummer best, late winter somewhat less effective). For felled trees, apply the herbicides to stem and stump tops immediately after cutting. Also, ORTHO Brush-B-Gon, Enforcer Brush Killer, and Vine-X are effective undiluted for treating cut-stumps and available in retail garden stores (safe to surrounding plants).
Saplings. Apply as basal sprays in mixed in a labeled basal oil product, vegetable oil or mineral oil with a penetrant, or fuel oil or diesel fuel (where permitted) using Garlon 4 as a 20-percent solution (5 pints per 3-gallon mix) when safety to surrounding vegetation is desired; or Stalker* as a 6- to 9-percent solution (1.5 to 2 pints per 3-gallon mix).
Seedlings and saplings. Thoroughly wet all leaves with one of the following herbicides in water with a surfactant (July to October): Arsenal AC* as a 0.75-percent solution (3 ounces per 3-gallon mix); Arsenal PowerLine* as a 1.5-percent solution (6 ounces per 3-gallon mix); Krenite S as a 15-percent solution (58 ounces per 3-gallon mix); Escort XP* at 1 ounce per acre; or when safety to surrounding vegetation is desired, Garlon 4 as a 1- to 2-percent solution (4 to 8 ounces per 3-gallon mix) or Garlon 3A as a 2-percent solution (8 ounces per 3-gallon mix).
* Nontarget plants may be killed or injured by root uptake.