Test Your Knowledge - December

The attractive fall color of poison ivy
Poison ivy showing attractive fall color
Joey Williamson, HGIC

Yes!

Poison ivy often has surprisingly beautiful fall color. Leaves are brilliant hues of yellow, gold, orange or red. Don’t pick these for your leaf collection though. The irritating oil that causes the poison ivy rash remains active throughout the fall and winter, and can even last for several years after vines are dead.

Poison ivy can be a small, erect shrub, a low groundcover or a vine. It is good to learn to recognize it in all stages. During the spring, summer and fall, poison ivy will show the classic “leaves of three” – actually compound leaves with three leaflets. The edges of the leaflets can be smooth, wavy, lobed or toothed.

During the winter look for white or grayish berries on mature poison ivy plants. These are attractive to birds.

Berries of poison ivy in winter
Berries of poison ivy in winter
Chris Evans, River to River CWMA, Bugwood.org

Mature vines on trees are attached by distinctive hairy aerial rootlets. These are very visible when plants are leafless.

Hairy aerial rootlets of poison ivy
Aerial rootlets of mature poison ivy
James H. Miller, USDA Forest Service, Bugwood.org

Several other plants are sometimes confused with poison ivy. Box elder looks the most similar in leaf, but is actually a type of maple. It grows as a tree, which poison ivy never does. Young box elder plants can be distinguished from poison ivy in that seedlings have opposite leaves, while poison ivy has alternate leaves.

Box elder leaves and seeds
Box elder leaves and seeds
Barbara Tokarska-Guzik, University of Silesia, Bugwood.org

Virginia creeper is a native vine that is often confused with poison ivy. While very young plants occasionally have only three leaflets, most plants will have five leaflets. Mature plants may have blue black berries. The vines climb by means of small circular holdfasts rather than aerial rootlets.

Five leaflets of Virginia creeper leaves
Virginia creeper showing 5 leaflets
Richard Old, XID Services, Inc., Bugwood.org

For more information on poison ivy, see HGIC 2307, Poison Ivy.

Karen Russ
HGIC Horticulture Specialist

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This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.