Scientific: Ailanthus altissima
Common: Tree of heaven, chouchun (Chinese)
Family: Simaroubaceae
Origin: Taiwan and northeastern China

Pronounciation: Aa-LAN-thus al-TIS-see-ma

Hardiness zones
USDA 2-11

Landscape Use: Unlike elsewhere across the United States, tree of heaven is a relatively rare tree in Phoenix landscapes that is found mostly in older residential neighborhoods and parks. It castes a light, filtered shade and provides an interesting architectural silhouette because of its upright habit and large compound leaves.

Form & Character: Deciduous, tough, upright, firm and stately, and messy...what an interesting combination!. Tree of heaven is the quintessential 'opportunistic' tree that thrives in full sun and disturbed areas across the entire contiguous United States.

Growth Habit: Rapid growth to 50 feet tall with lesser spread, somewhat soft wooded. Tree of heaven is notorious for producing root suckers AND has the capacity to reseed, sometimes profusely.

Foliage/Texture: Large, alternate, medium green, even-pinnately compound leaves with 13 to 25 leaflets per leaf, leaves 12 to 36 inches long, whereas individual leaflets are ovate to lanceolate, with prominent veination, and are 3 to 5 inches long. Younger stems are heavily laden with lenticels. Trunk bark of mature trees ranges from smooth to ridged and furrowed and grayish in color; medium coarse texture.

Flowers & Fruits: Diecious, small yellow-greenish (male flowers) to reddish (female flowers), arranged terminally in large panicles up to 20 inches in length. Winged fruit are borne in clusters.

Seasonal Color: In Phoenix, tree of heaven produces only limited yellow leaf late fall color.

Temperature: Extremely hardy of heat and cold.

Light: Full sun, though slightly prone to trunk sunscald.

Soil: Tolerant

Watering: Requires regular irrigation.

Pruning: Young trees need early and rigorous training to develop a strong matrix of scaffold branches. Established trees require limited pruning, usually only to raise the crown in order to elevate the canopy base. Be vigilant to remove unwanted root suckers and seedlings.

Propagation: Seed, vegetative cutting.

Disease and pests: Generally little to no problems in Phoenix.

Additional comments: The tree of heaven is renown for both positive and negative reasons, it is the true urban 'mystery trash' tree. The tree was first brought from China to Europe in the 1740s and then to the eastern United States in 1784. It is about as tough a deciduous tree as there is in the world when it comes to thriving in densely populated cities and polluted urban conditions. Yet, the same characteristic that enable it to thrive and proliferate in the midst of people, especially in climates more temperate and moist than Arizona, also give this tree an infamous reputation. The tree of heaven has vigorously naturalized in many parts of the world and gained a reputation for being highly invasive. Because of its checkered past, Ailanthus is now a part of American cultural lore and can be found growing in 40 of the 50 United States. Nearly every part of the tree of heaven has some application in Chinese traditional medicine.

Special note: Tree of heaven served as the central metaphor and subject matter of the best-selling American novel A Tree Grows in Brooklyn by writer Betty Smith.