Photo: The leaves and flowers of the Tree of Heaven. Photo credit.
Last month we focused on one of Rock Creek Park’s most common native tree species. This month we switch to highlight one of its most invasive, Tree of Heaven also known as Stinking Sumac, Varnish-tree, Stink-tree, and Ailanthus altissima.
It started as a shade tree, now it's here.
While the name may make the tree sound heavenly, it is certainly no angel in and around Rock Creek Park. It is incredibly invasive and not just locally. To date, the tree has been labeled invasive in over 30 states across the US. Originating in China, Tree of Heaven was first introduced as a shade species in the United States in the 1700s. Since then, the tree has spread vigorously in human-disturbed areas wherever it can take root and grow. (It grows practically anywhere.)
ID this Tree!
The tree has pale gray bark and can grow up to 80 feet in height. Its large compound leaves are made of smaller leaflets sometimes found in clumps of up to 40 per leaf. Male versions of the tree (yes, the trees can be either male or female, this is called dioecious) also emit a foul odor to attract pollinators. Some people claim that it smells like old peanut-butter.
Tree of Heaven also has some other unique characteristics that make it particularly challenging to control. The tree produces chemicals that prevent the establishment of other plants in their direct vicinity. Larger specimens also can feature very extensive root systems that can damage pipes and sewers.
Bark of the Tree of Heaven
The moral of the story: never plant Tree of Heaven in your yard!
Native alternatives to getting the shade you crave include the black walnut and fringe-tree. Manual removal of saplings can be effective if the root system is removed, but cutting larger trees can be counterproductive due to the tree's ability to produce stump sprouts and root suckers that make it even more difficult to manually remove. Chemical treatment is most effective.
DID YOU KNOW: The critically acclaimed novel A Tree Grows in Brooklyn by Betty Smith uses the Tree of Heaven as a metaphor.
This article was written by John Maleri.