As we start to enjoy the outdoor areas around our homes and communities this spring, be on the lookout for poison ivy, Toxicodendron radicans. Although not everyone is sensitive to this plant, many people develop an uncomfortable, itchy, blistering rash when the plant resins – urushiols – come in contact with the skin. Avoiding the plant may be difficult because it can masquerade as a vine, groundcover or shrub.
Poison ivy is able to grow in full sun or shade and in wet or dry conditions. Although it becomes dormant in winter, the resin on the stems may still transfer to clothing or skin, causing a skin reaction. Although not affected by it, pets can carry the resin on their fur and transfer it to their owners.
Poison ivy can be identified by three leaves – remember "leaves of three, not for me" – that are of equal size and connected at a central point. The leaves are longer than they are wide. New leaves are dark green in summer and change to reddish-orange in the fall. They have small white flowers in the spring, followed later by white berries. Stems are brownish-gray and have wiry hairs. Vines are capable of growing high into a tree, and they develop a stem several inches in diameter with dense hairs.
Once identified, be careful if attempting to remove the plant. Wear protective clothing including long pants and long sleeves. Any gloves, clothing or tools used and not properly cleaned or disposed of can carry the plant resin which can result in skin exposure later when you are least expecting it.
The plant should be dug up, removing all of its roots to prevent its return, or treat the plant with an herbicide that is applied to the leaves. Check with University of Illinois Extension for an appropriate herbicide.
Expect that poison ivy may come back and be prepared to retreat. You will want to keep pets and children clear of the area until you're certain the plant is gone. Never burn poison ivy as the smoke may cause lung irritation.
Darlie Simerson is a University of Illinois Extension master gardener for Kane County. The “Learning to Grow” column runs weekly during warmer months of the year. Call the extension office at 630-584-6166 or visit web.extension.illinois.edu/dkk for more information. Feedback on this column can be sent to firstname.lastname@example.org.