Warm weather hiking in the United States is always accompanied by a fair amount of caution. Irritating plants like poison sumac, poison oak, and poison ivy are bound to grow in temperate areas across the country. You’ll be able to identify and avoid them after reading this article.
Continue reading to learn more about poison sumac and the plants that mimic it in appearance. Plant identification skills are valuable, especially if you’re out in nature without a guidebook or ID app. You won’t have to play guessing games with whether something could have negative health effects.
Why is Poison Sumac Irritating?
Poison sumac (Toxicodendron vernix) contains compounds that make it painful for herbivores to eat. Every part of the plant is coated with an irritating resin called urushiol. This doesn’t bother birds or herbivores, which gladly eat the berries and leaves.
Human susceptibility to urushiol is another story. Our skin finds this natural resin very irritating. There are different levels of irritation.
In some people, skin-to-plant contact with poison sumac causes only a rash. In others, it can trigger a full body allergy that requires medical attention.
A Few Plants That Look Like Poison Sumac
Before diving into our description of lookalikes to poison sumac, let’s do a little refresher on the traits of poison sumac.
Poison sumac looks different than poison oak and poison ivy. Instead of just three leaves or leaves that appear similar to oak tree leaves, poison sumac has a stem with many leaflets.
The leaflets number between 7 to 13 on every stem. Each leaflet is oval-shaped with a pointed tip. Unlike poison oak, the leaves are smooth. Take our word for it – don’t feel poison sumac leaves to find out!
In the fall, poison sumac leaves turn red. Since this plant grows most commonly in the southern United States, the months in which the leaves are red usually range from October to March. Other populations thrive near the Great Lakes and New England regions.
Poison sumac grows in two shapes: shrubs and small trees. They prefer waterlogged areas like swamps and bogs. A great way to spot them is to check if the plant has its roots in the water.
1. Boxelder
Scientific name: Acer negundo
Boxelder looks a lot like poison ivy, and thus can scare many hikers away from trails or waypoints if it is too abundant along the edges. However, boxelder doesn’t pose a health risk at all. You can tell it apart from poison sumac by way of the shape and number of its leaves.
This plant’s leaves are compound like poison sumac. However, there are only 3 to 5 leaflets, not 7 to 13. They have jagged edges – a term naturalists call ‘toothed’ – and don’t turn red when the weather gets cold.
2. Smooth Sumac
Scientific name: Rhus glabra
Smooth sumac grows in a shrub form similar to poison sumac. However, it’s unlikely that you’ll have to look too closely at smooth sumac to tell it apart from poison sumac.
It has many more leaflets per leaf than poison sumac does – up to 31! To accommodate the large number of leaflets per leaf, each leaflet is long and pointed. The edges of the leaflets are toothed as well.
In the late spring and early fall, smooth sumac produces fruits. This is a surefire way to tell poison sumac apart from smooth sumac. The former’s berries are white while the non-poisonous relative’s berries are bright red.
3. Winged Sumac
Scientific name: Rhus copallinum
Winged sumac looks a lot like smooth sumac. It grows in a shrub-like shape too. This species’ name stems from a unique trait that will tell it apart from poison sumac upon close inspection.
There are tiny ‘wings’ on each side of the leaf stalk. When viewed from above, the leaf’s central stem looks like a wide ribbon.
They also have red berries in the fall, so it’s easy to tell them apart from poison sumac.
4. Black Walnut Tree
Scientific name: Juglans nigra
You won’t mistake a mature black walnut tree for poison sumac since the nut trees grow over 40 feet tall when mature. Saplings of each species are another story.
The black walnut tree has pinnately compound leaves like poison sumac. They average about 14 leaflets, which is similar to the 7 to 13 leaflets on the skin-irritating plant.
You’ll be able to tell them apart by the teeth on the leaves. Black walnut leaflets have ragged, serrated edges. Poison sumac leaflets are smooth and pointed.
The differences are even easier to recognize in the fall. Black walnut trees produce large walnuts that fall off and collect around the base of the trunk. Their leaves turn bright yellow too.
5. Tree of Heaven
Scientific name: Ailanthus altissima
The tree of heaven is anything but heavenly for the forester who wants to keep native species around. This invasive and hardy tree is originally from southeast Asia.
It is a host to the spotted lanternfly, an invasive insect that threatens North American wildlife. While it doesn’t cause skin rashes, it contains compounds that leach into the soil and prevent other trees from growing.
Both poison sumac and the tree of heaven have compound leaves. The leaflets may look similar from far away, but upon closer inspection, they’re quite different. Poison sumac leaflets number between 7 and 13 per leaf. Tree of heaven leaflets can reach upwards of 40!
6. Staghorn Sumac
Scientific name: Rhus typhina
Staghorn sumac is so named because of the shape of the spike the fruit balances on. It’s very similar to smooth sumac but it has a furry edge to each of the fruits on the central spike. If you see it in the fall when the red fruits are visible, it will be easy to cross it off the list of potential poison sumac.
This shrub can grow up to 16 feet tall and usually appears at maturity like a small tree. They are weaker than most hardwoods and can be pruned into various shapes.
Anna is a wildlife biologist who graduated from Texas A&M in 2020. She enjoys studying and learning about wild birds and wildlife of all types.