Photo: Tree of Heaven, Margaret Fisher
Cindy Speas, Chair
Fairfax County Tree Commission
In summer many folks travel to the Shenandoah Valley and beyond for recreational opportunities. Driving in any direction from northern Virginia in the growing season, you will see an attractive-looking tree everywhere along the highways and byways. The dramatic clusters of seeds are so large they look like giant flowers among the leaves. It’s not native walnut or native sumac—it is Ailanthus altissima, commonly called Tree-of-Heaven. Disturbed areas and rights-of-way along roads are perfect locations for this opportunistic pest to colonize. Ailanthus is popping up in suburbia as well, and even tree-loving experts are calling for us to remove these attractive and fast-growing specimens from our properties as soon as possible.
Tree of Heaven with Spotted Lanternfly inset, Margaret Fisher
Ailanthus was imported from China and widely distributed in the United States as an ornamental in the late 1700s and 1800s. Its behavior, though, is far from heavenly—it spreads aggressively through root sprouting and huge seed production; it grows to maturity rapidly with a very long taproot; it is characterized by its terrible odor; and it poisons the ground around its roots with chemicals, in a process called allelopathy. This prevents native trees and plants from growing nearby, allowing Ailanthus to spread quickly and dominate our landscape.
Even worse, Ailanthus is the preferred food source for a new invasive insect—the Spotted Lanternfly (SLF). In spite of state quarantines, this destructive pest has been found in Fairfax County. It is a major threat to some of Virginia’s agricultural areas, especially our vineyards, peach orchards, and hops fields. It also is a threat to native tree species like oaks and maples that thrive in our yards. Forest Pest Branch asks all residents to report Ailanthus following the instructions in this brochure and report Spotted Lanternfly sightings here.
Some may still ask why these non-native trees should be removed—don’t they at least provide shade and shelter in a warming world? They certainly can, but they crowd out our native oaks, beeches, hickories and maples, as well as fail to provide the critical food resources that native insects and other animals need to live and reproduce in a fully functioning, healthy ecosystem. If a plant like this is killing off or threatening major parts of our local natural food web, the entire system will eventually collapse. And we will lose our native tree canopy along the way.
How can we stop the spread of this nasty invasive? First, of course, do not purchase it! So be sure to learn how to identify it. You can become familiar with the iNaturalist app on your smartphone or use other online resources to name the plant. When in doubt, try crushing a leaf and smelling it: the odor is similar to rancid peanut butter. Second, remove the tree if it is growing on your land. This pest, however, thrives when simply cut down, so you will have to kill the root system right away. There are some very useful resources to help landowners eliminate this threat safely and efficiently. Blue Ridge Prism has excellent fact sheets with details about herbicide use for this and other invasive species.
Visit Plant Nova Natives for more information about invasives and their destructive roles in our native environment. It would be truly heavenly if we could eliminate a threat like the Tree-of-Heaven.