Common Name: Tree of Heaven
Scientific Name: Ailanthus altissima (Mill.) Swingle
Synonyms: Chinese sumac, stinking sumac, stink tree, tree-of-heaven
Legal Status: Restricted
Propagation and sale of this plant are prohibited in Minnesota. Transportation is only allowed when in compliance with Minnesota Statute 18.82. Although Restricted Noxious Weeds are not required to be controlled or eradicated by law, landowners are strongly encouraged to manage these invasive plants on their properties in order to reduce spread into new areas. Minnesota Noxious Weed Law.
Tree of heaven is native to China. It was brought to the U.S. in the late 1700s as an ornamental shade tree. Today this tree is found in most of the continental U.S. states and Hawaii. It looks similar to and could be confused with staghorn sumac, ash and walnut. It has a strong, offensive odor, especially when flowering, that can help distinguish it.
- A deciduous tree that can reach 70 ft. in height, the bark on the main trunk is smooth and gray and the twigs are light brown. Plants are dioecious, meaning male and female parts are on different plants.
- The leaves are large (1- 4 feet long), alternate, and compound with 11- 41 smaller leaflets.
- Flowers are small, yellowish-green, and arranged in large, showy clusters at the end of the leaves.
- Fruit are flat, twisted, winged fruits called samaras (similar to the fruit that maple trees produce) that hang in long clusters. Each samara contains one seed.
- Fast-growing, horizontal roots form a wide-spreading system that sends up new sprouts up to 90 feet from the parent stem.
Tree of heaven thrives in areas of disturbance and in a wide range of soil types and conditions, including drought. It grows best in full sun and is fairly intolerant of shade and saturated soils. It is known as an adaptable and pollution-tolerant tree for urban settings and can grow in tight rooting spaces where other trees may not be able to grow. It is generally more common in disturbed urban and rural areas, such as roadsides and fence rows. In natural areas, it can be found on floodplains and other disturbed sites, open woodlands, and rock outcrops.
Means of spread and distribution
This species is highly adaptable and tolerant of disturbance. Females are prolific seeders; a single female tree may produce up to 325,000 seeds per year. Therefore, the females must be targeted for control to prevent further seed production. It also spreads aggressively through vegetative means, in response to above-ground cutting or root breaking. Root fragments found in infested soil may start new populations if brought to a new area.
Tree of heaven is reported in most U.S. states, but it is most abundant in the Northeast and California. There has been only one tree of heaven report in Minnesota.
This tree is common to urban areas where it can cause damage to sewers, pavement, and building foundations. It is a fast growing tree and a prolific seeder.
In natural ecosystems, it will establish dense monocultures that outcompete natives. Tree of heaven releases allelopathic chemicals into the soil which is toxic to other species, this helps it to establish and spread quickly without competition.
Prevention and management
- Once established, tree of heaven is difficult to control. For all management options, infestation sites will need to be monitored and treated repeatedly until the seedbanks and rootstocks are depleted.
- Be sure to confirm identification before controlling, so you do not mistake a native species like staghorn sumac. Pay special attention to controlling female trees to reduce seed production.
- Do not plant tree of heaven or spread its seeds when moving soil from infested areas.
- Small infestations can be controlled manually by pulling and digging. Very young seedlings can be pulled easily by hand. Be sure to remove the entire root to prevent resprouting.
- Large infestations can be controlled with either foliar or cut-stem herbicide applications. For specific herbicide recommendations, contact your University of Minnesota Regional Extension Educator.