Invasive plant species are an ever-present problem for land managers and conservationists. Properly managing invasive species is a task that many within the conservation world deal with on a regular basis. Being able to properly identify invasive species of plants is crucial so effective action can be taken to remove or manage the identified species. Conversely it is also very important to be able to correctly identify beneficial native plants that may look very similar to an invasive plant species. Properly distinguishing “lookalikes” ensures that native plants are not mistakenly removed or chemically treated during management projects.
One of the best examples of such lookalikes is Ainlanthus altissima (Tree of Heaven) and two native sumacs to the region, Rhus typhina (staghorn sumac) and Rhus glabra (smooth sumac). At a quick glance Tree of Heaven and native sumac may seem indistinguishable, or at least confusing, but upon closer inspection there are several key characteristics to look for that will quickly distinguish the invasive Ailanthus from the native sumacs.
If you can reach the leaves or a stem of the tree and break off a leaf or small twig you will be able to decipher which plant you have encountered. Ailanthus has a very pungent aroma at a broken section of a twig or crushed leaf. Some describe it as rancid peanut butter or burnt rubber. Sumac on the other hand does not have a very pungent odor and the leaves will have an average, mild vegetative scent.
Each plants’ leaves are also different, which can be observed on the leaflets (both species have compound leaves where there are numerous leaflets along one leaf stem). The leaflets of both sumacs are serrated or toothed while Ailanthus has almost entirely smooth leaflet edges (sumac on the left, ailanthus on the right in the picture to the right).
Also, Ailanthus leaflets contain one or more glands that can be found at the base of the leaflet. These glands are not present on sumac leaves.
One last distinguishing trait of each plant can be observed in late summer or early fall and that is the seed or fruit cluster. If the tree has finished flowering and produced fruit or seed, this is a great way to quickly identify the tree, even if at a distance. Sumacs have a panicle of flowers that produces a deep red cluster of fuzzy fruits which can easily persist into winter. Ailanthus produces samaras that hang in clusters and turn a dull orange/brown color.
Using these characteristics (barring winter months when seeds and leaves may not be present) it can be very easy, even for an average property owner to distinguish Ailanthus from our native sumacs. Don’t rush to judgment though, look closely for the key characteristics.
Native sumac offers a great food source and habitat when found in natural areas and NJ Audubon encourages property owners to leave it if found. Ailanthus on the other hand should be removed using appropriate techniques, see http://wiki.bugwood.org/Ailanthus_altissima for removal guidance.
(Photo Chuck Bargeron, University of Georgie, bugwood.org)
Proper plant identification is one of the many skillsets NJ Audubon staff use to ensure that we are undertaking stewardship activities and managing habitat to produce the most positive ecological results.
Text and all photos except Ailanthus seeds by Ryan Hasko.