Poison ivy and poison oak are quite variable. Either may grow as a ground vine, a climbing vine, or a small bush. Their branches may be green and tender looking or brown and woody, depending upon age. The leaves may be pointed, or rounded and lobed like oak leaves: however, they are always in clusters of three separate leaflets, the middle one having a longer stalk.
Green in summer, they turn red in fall when small bunches of white berries appear. Poison sumac, a tall shrub or small tree, thrives in bogs, swamps, or other wet areas. Its 7 to 13 leaflets are paired on a red stem, and its berries are greenish white.
To get rid of a small patch of these plants, dig them up by the roots in early spring or late M. During the growing season, cut them to the ground and cover with black plastic, cardboard, or a 6-inch layer of straw. Mow a large infestation in midsummer, then plow or rototill.
The herbicide Ammate, sold at many garden centers, is also effective. Follow directions carefully. It can destroy desirable plants too: so spray selectively and only when the air is still.
When walking in likely areas, cover your legs, feet, hands, and arms. If you should touch a plant, promptly wash and rinse contact areas twice with strong soap. Wash contaminated clothing. Wash tools too: oil on them can stay potent for years.
After contact, most people get a red, itchy rash with tiny, oozing blisters. Soothe the itching with cold-water compresses: or apply Burow’s solution in a 1:40 concentration, followed by plain calamine lotion. It may also help to take an antihistamine pill before going to bed. In the woods, you can get emergency relief by rubbing the affected area with crushed leaves and stems of the orange- or yellow-flowered jewelweed. For a widespread rash or one on your face or genital area, see your doctor.