Tree-of-heaven Ailanthus altissima , commonly referred to as ailanthus, is a rapidly growing deciduous tree native to both northeast and central China, as well as Taiwan. It was first introduced into the United States in the Philadelphia area in the late s. Immigrants later introduced tree-of-heaven to the West Coast in the s. The tree was initially valued as a unique, fast-growing ornamental shade tree with the ability to grow on a wide range of site conditions, tolerating poor soils and air quality.
By the early s, the tree began losing popularity due to its "weedy" nature, prolific root sprouting, and foul odor. Tree-of-heaven has spread and become a common invasive plant in urban, agricultural, and forested areas. Size: Tree-of-heaven has rapid growth and can grow into a large tree, reaching heights of 80 feet and up to 6 feet in diameter. Bark: The bark of tree-of-heaven is smooth and brownish-green when young, eventually turning light brown to gray, resembling the skin of a cantaloupe.
Leaves: Tree-of-heaven leaves are pinnately compound, meaning they have a central stem to which leaflets are attached on each side. One leaf can range in length from 1 to 4 feet with anywhere from 10 to 40 leaflets. The leaflets are lance-shaped with smooth or "entire" margins. At the base of each leaflet are one to two protruding bumps called glandular teeth. When crushed, the leaves and all plant parts give off a strong, offensive odor.
Twigs: The twigs of tree-of-heaven are alternate on the tree, stout, greenish to brown in color, and lack a terminal bud. They have large V- or heart-shaped leaf scars. The twigs easily break to expose the large, spongy, brown center, or pith.
Seeds : Seeds on female trees are a 1-toinch-long twisted samara, or wing. There is one seed per samara. The samaras are found in clusters, which often hang on the tree through winter.
