Ailanthus altissima
WARNING: LOCALLY INVASIVE SPECIES
Common Name: tree of Heaven
Type: Tree
Family: Simaroubaceae
Native Range: Northern China
Zone: 4 to 8
Height: 40.00 to 80.00 feet
Spread: 30.00 to 60.00 feet
Bloom Time: June
Bloom Description: Greenish
Sun: Full sun to part shade
Water: Dry to medium
Maintenance: High
Flower: Showy, Fragrant
Leaf: Fragrant
Tolerate: Drought, Air Pollution
Ailanthus altissima is listed as an exotic invasive species to Missouri and the Midwest by the Midwest Invasive Plant Network. The species should not be planted in the Midwest.

Culture

Easily grown in average, dry to medium soils in full sun to part shade. Tolerates a wide range of soils including poor ones. Tolerates close to full shade. Quite tolerant of urban pollution. This is a suckering plant that can form large colonies or thickets that tend to choke out native plants. Spreads invasively by aggressive root suckering and self-seeding. Most homeowners are more interested in eradicating this plant than in growing it ornamentally.

Noteworthy Characteristics

Native to China, tree of heaven was introduced into New York City in 1820 as a street tree and food source for silkworm caterpillars. It has now naturalized throughout much of the United States. In many areas it has become a noxious weed. It is extremely fast-growing and it will grow almost anywhere. It can literally grow up from a crack in the sidewalk, and is strong enough to push up through the blacktop surface of a parking lot. It not only grows in cities, but may also be found in the country along roads, fencerows, clearings and wood margins. It can grow up to 60-80’ tall with a loose, open, sometimes graceful form, but is usually seen growing much shorter in urban areas. Wood is weak and tall trees in exposed areas may easily top out in strong winds. Odd-pinnate compound leaves (most often 11-25 leaflets each) tend to give it a certain tropical appearance. Leaflets have large gland-tipped teeth at the base. These teeth distinguish it from the sumacs, which also have long compound leaves. Mostly dioecious (separate male and female trees), but some perfect flowers exist. Male flowers have an unpleasant odor. Actually all parts of the tree have an unpleasant odor. Blooms early summer (June-July). Flowers are greenish. Female flowers produce seeds (twisted samaras) in clusters ripening to reddish-brown in September. Smooth pale gray bark. The genus name comes from the Amboinese (Malukan) word ailanto meaning tree of god and the specific epithet is a superlative form of the Latin word meaning “high”, hence the common name of tree of heaven. This is the tree featured in A Tree Grows in Brooklyn, by Betty Smith (1942), a coming of age novel about a young girl growing up in a Brooklyn tenement who finds the toughness and persistence of Ailanthus, growing up from the sidewalk cracks, to be an aspirational metaphor for overcoming the adversities of her own life.

Problems

No serious insect or disease problems. Invasive and difficult to eradicate. Weak wooded. Short-lived. Messy.

Garden Uses

This is not a good landscape tree, however if it is to be grown, female trees are generally preferable to male trees. It will grow and prosper in areas of poor soils where few other trees will flourish.