Tree-of-heaven, Ailanthus altissima, was originally from China and became a popular landscape shade tree in the 1800’s. However, its rapid growth, aggressive spread, and native habitat disruption have made it a global problem. Reproducing rapidly through dense root suckers and wind dispersal of its “winged” seeds (samaras), tree-of-heaven has proven incredibly difficult to control. A mature tree can produce 325,000 seeds each year, and the extensive root system can cause major damage to sewers, sidewalks and foundations. These trees are drought resistant, tolerant of many soil conditions, and grow along roadsides, in alleyways, vacant lots, and urban parks. Tree-of-heaven can be identified by several distinctive traits. The bark is grey with diamond shaped fissures and a cantaloupe-like texture. The leaflets have smooth edges with two glandular notches (teeth) at the base. The twigs have heart-shaped leaf scars with spongy brown center (pith). The seeds form in clusters of single seeded samaras that are 1-2 inches long and are green, yellow, red, or brown. Flowers are small, pale yellow-green and grow in upright clusters. All plant parts smell like rancid peanut butter.
Actions you can take
Do not plant tree-of-heaven. It is included on the California State Noxious Weeds List as an invasive plant species to avoid. Tree-of-heaven attracts other invasive pests, including the brown marmorated stink bug and spotted lanternfly, which prefer tree-of-heaven as a host and can damage crops and ornamental plants. If you have this tree on your property, consult with an arborist about removal. Simply cutting or pruning this tree triggers the growth of new suckers that can emerge up to 50 feet away, leading to rapid and uncontrollable spread. To learn more about tree-of-heaven visit https://www.cal-ipc.org/plants/profile/ailanthus-altissima-profile/.