Despite its serene name, Ailanthus altissima, more commonly known as Tree of Heaven, is less than a gift from above. A non-native invasive originating in China, Tree of Heaven spreads rapidly, outpacing native plants in its growth and often killing them through chemical secretions in the soil. They also serve as a prime host for another harmful invasive species, the spotted lanternfly.
Unfortunately, mitigating the spread of this plant is not as simple as just cutting down the trees you see. Learn how you can do your part to slow the spread of this pernicious pest.
- Identifying Tree of Heaven
Tree of Heaven has several distinctive features. It has bark described as resembling cantaloupe, with long compound leaves that have two distinctive “bumps” or “notches” at the base. The leaves have a distinctive rancid peanut or cat urine-like smell.
This time of year (late summer to fall) Tree of Heaven is very distinctive, with the female tree sporting peach/salmon/coral colored seeds in clusters.
If you see any mature female trees on public land, particularly in Arlington and Alexandria, please identify them using the iNaturalist application. This will allow local government officials and researchers to track the spread of these trees. When submitting photos of the trees, please submit photos that show the seed clusters, as well as another photo or two that show the characteristic leaves and bark of the tree to ensure accurate tree ID.
- Managing Tree of Heaven
As unintuitive as it may seem, cutting down tree of heaven ends up creating a Hydra-like issue: it triggers resprouting from the roots and the stump of the tree, leading to multiple trees taking the place of the original tree.
Only trained staff or contractors should be removing tree of heaven (or any trees!) from public land. For those aiming to mitigate tree of heaven on their private property, you can follow the below steps:
- If the tree is still just a seedling/very small sapling that has NOT produced seeds, you can pull the tree out, ensuring all roots are removed. It’s a bit easier to do this after it has rained when the soil is looser.
- If the tree is producing seeds and/or is relatively well-established, apply a targeted herbicide, being careful to not apply it to surrounding plants. The two recommended options are:
- Basal bark method: Apply a solution of a 20-25% concentration of oil-soluble triclopyr ester product in an oil-based carrier is highly effective. Using a handheld or backpack sprayer, apply the mixture in a continuous 12-inch wide band around the tree base. The basal bark method requires no cutting and is generally used for trees that are less than six inches in diameter, though larger stems (up to 16 inches) may also be treated effectively
- Stem injection (hack-and-squirt) method: This technique is very effective when applied during the summer. It requires first making downward-angled cuts into the sapwood around the tree trunk at a comfortable height, using a hand ax. With a spray bottle or wand, squirt the selected product into the cuts within a minute or two, so that the bottom of the cut is covered but the liquid doesn’t run out. This method can be used with trees of any size, though it is most effective with stems over two inches in diameter. A triclopyr product is most often recommended.
- Once the tree has died, then you can safely remove it.
- Be on the Lookout for the Spotted Lanternfly
Tree of Heaven is a key host for the spotted lanternfly. Eggs are laid in late fall and can be found on any flat surface such as trailers, logging equipment, and on tree bark. They hatch as “nymphs” in mid-April and become adults in July.
Clockwise from top left: Adult showing hind wings, adult with folded wings, early black and white nymphs, full-grown nymphs showing red, and egg masses.
If you see any spotted lanternflies, please kill nymphs/adults as able, then report the sighting and location with either a photo of the insect or the sample itself to your local Virginia Cooperative Extensive office.
For more information on Tree of Heaven, consult the Virginia Department of Forestry’s article on Ailanthus Control Methods and their Guide for Virginia Landowners on the Control and Utilization of Tree-of-Heaven. For more information on spotted lanternflies, consult the Virginia Cooperative Extension’s resources on Spotted Lanternfly in Virginia.