Now is the Time to Tackle Tree of Heaven

Ailanthus altissima, or Tree of Heaven, is one of the most aggressive plant invaders in our area, ranked as “high” on the Virginia Department of Conservation and Recreation’s list of invasive species. Our friends at Blue Ridge PRISM recently issued an alert saying that now is the time to take a swing at this pernicious pest.

What makes Ailanthus such a problem? Among other things, it out-competes desirable plants by establishing itself in disturbed soils, such as those along transportation corridors, or by taking advantage of gaps in mature forests and displacing native tree species. Ailanthus also increases its chances of survival by releasing herbicidal toxins into the soil. Plus, its roots can penetrate sewer lines and building foundations. Making matters worse, it’s one of the preferred host plants for the Spotted Lanternfly, a new invasive insect pest in Virginia that poses a threat to the state’s grape, orchard and wood-product industries, according to Virginia Cooperative Extension.

Blue Ridge PRISM (Partnership for Invasive Species Management) warns that simply cutting Tree of Heaven to the ground is not enough to eradicate plants. The freshly cut stump must be treated with an herbicide or else dozens of shoots will sprout from the wound. Likewise, pulling up seedlings will be futile if you fail remove the entire root. Blue Ridge PRISM outlines a range of effective control methods in their alert and in their Tree of Heaven factsheet.

These resources also help to distinguish Ailanthus from several native look-alikes, such as Black Walnut, Ash, Staghorn Sumac, and Smooth Sumac. One way to tell the difference is the sniff test: crush an Ailanthus leaf, and you will get a strong whiff of a scent variously described as that of burnt coffee or rancid peanut butter. This is due to two small glands at the base of each leaflet, which can also aid in making an accurate identification.

Ailanthus leaflet (left) and winged Sumac leaflet (right)

But, be careful to wear gloves if you plan on touching Tree of Heaven. Handling the leaves and branches of this tree can cause a skin rash due to exposure to the sap. Be especially careful if you have open wounds on your arms or hands. The sap has been known to cause myocarditis, or inflammation of the heart muscle. Reported symptoms include fever and chills, chest pain that radiates down both arms, and shortness of breath.