Poison sumac now bears the Latin name Toxicodendron vernix, replacing the older name, Rhus vernix. It often grows next to Cinnamon ferns (Osmunda cinnamomea), marsh marigolds (Caltha palustris), cattails (Typha), and winterberry holly (Ilex verticillata).
What Is Poison Sumac?
Poison sumac is a shrub (some consider it a small tree) that grows in wet areas. All parts of poison sumac are poisonous.
One key to proper identification is studying the shrub's individual plant parts:
- Leaf (color and shape)
- Stem (color)
You increase your odds of identification if you know what all of these plant parts look like, rather than knowing the appearance of just one.
A second key to successful identification is learning what the plant looks like from season to season, so you can recognize it when you encounter it during various months. In addition to the practical benefit of knowing what poison sumac looks like in fall, it is also simply enjoyable to view its fall foliage. Its autumn display is every bit as good as the more familiar ones we appreciate from the great fall color trees.
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The edge, or margin, of poison sumac's leaflet is considered "entire" in plant-identification terminology, and it displays a midrib of a lighter color. A leaf margin that is entire is smooth; it lacks the "teeth" that the leaf edge of a Roger's flower (Rodgersia) has, for example.Continue to 2 of 13 below.
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Pinnately Compound Leaves
The shape of poison sumac leaves is described by botanists as a "pinnately compound." "Pinnate" means resembling a feather; "compound" means that, instead of one, unified structure, a plant's leaf is really composed of multiple leaflets joined by stems.
Poison sumac has leaves made up of 7 to 13 leaflets. While the exact number varies, it is always an odd number. That's because, while most of the leaflets form matching pairs (one across from the other), there's always one lone leaflet at the tip of the compound leaf, which gives it the shape of a feather.Continue to 3 of 13 below.
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The stems of poison sumac leaves further help us to identify the plant. The bright red color of the stems is one of the first things you'd want to look for in the spring to distinguish the shrub from nonpoisonous varieties of sumac.Continue to 4 of 13 below.
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Spring and Summer Berries
The berries of poison sumac start out green in spring and remain that color for much of the summer. They grow in clusters that are quite distinct from the berry clusters of nonpoisonous sumacs (Rhus typhina, for example), in terms of color, shape, and texture.Continue to 5 of 13 below.
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Oddly Shaped Berries
One distinguishing feature of the berries of poison sumac is that they aren't perfectly round. Although toxic to the touch for humans, poison sumac berries are not toxic to birds. Many birds, including quail, treat the berries as a food source in winter.Continue to 6 of 13 below.
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The foliage of poison sumac shrub changes its color in fall, as do the berries. Like poison ivy, the color of poison sumac's mature berry is whitish. The fact that the berry color of these two noxious weeds is so unusual makes it another distinguishing feature.Continue to 7 of 13 below.
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Orange Fall Foliage
The fall foliage of poison sumac is magnificent, especially because the leaves don't all turn the same color at the same time. This makes for some beautiful combinations. When all of the leaves finally do become the same color, that color can be orange, yellow, or red.Continue to 8 of 13 below.
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Yellow Fall Foliage
Poison sumac with yellow fall foliage can rival that of birch trees.Continue to 9 of 13 below.
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Red Fall Foliage
The most striking single color poison sumac's fall foliage can become is red, which has a brightness and crispness that rivals the fall foliage of red maple trees, albeit on a smaller scale.Continue to 10 of 13 below.
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Mixed Fall Foliage
When the autumn leaves of poison sumac have mixed colors, possible combinations include:
- Yellow and pink
- Red and pink
- Red, pink, and yellow
In all three cases, a tinge of green may remain to add yet another color.Continue to 11 of 13 below.
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Poison sumac grows to be 6 to 25 feet high. The new bark on the branches is relatively smooth. If you learn how to identify the plant by its bark, then you will be able to avoid coming into contact with poison sumac in winter (after it has lost its leaves).Continue to 12 of 13 below.
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The old bark of poison sumac is much rougher in texture than the newer bark.Continue to 13 of 13 below.
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A Harmless Relative
Not all sumacs are poisonous. Most sumac shrubs are quite harmless (nonpoisonous) and potentially desirable landscaping elements, which is another reason why you should identify poison sumac properly. There is no reason to pass up the great fall color of nonpoisonous sumac simply because they have "sumac" in their common name.
One of the easiest ways to distinguish between the two is by examining the berries or seeds. Nonpoisonous sumac forms its seeds in a red, fuzzy seed tuft that offers some ornamental value. This seed-tuft looks feathery from a distance and is soft to the touch. The seeds are tightly packed within the seed tuft. Wild birds eat the seeds in winter.
Toxicity of Poison Sumac
Poison sumac contains the same toxin, urushiol, that’s found in poison ivy and poison oak, but the toxin is much more concentrated in poison sumac. All parts of the plant contain this toxin, and it even remains active in dead poison sumac plants.
If you need to work with poison sumac in your garden, always wear protective clothing: long sleeves and pants, rubber gloves, and boots. Thoroughly hose down your boots and gloves after you’re done in the garden, and immediately wash your clothes. It's ideal to take a shower as well just in case there's some resin on your body.
Poison Sumac. Colorado State University.
Beware of Poison Sumac (Rhus Vernix). University of New Hampshire Cooperative Extension.