Poison Ivy
Woody or Vine weed
Poison ivy (Toxicodendron radicans) is a native woody perennial found across much of the United States. Gardeners and growers notice it because nearly every part of the plant contains urushiol, an oily compound that causes an itchy, blistering rash on skin, making it one of the most unwelcome weeds to find along fences, wood edges, and garden borders.
How to identify it
Look for compound leaves made up of three leaflets, the source of the old saying "leaves of three, let it be." The middle leaflet sits on a longer stalk than the two side leaflets, and leaf edges may be smooth, toothed, or lobed. It grows as a low ground creeper, an upright shrub, or a climbing vine, with mature vines clinging to trees by dense reddish or brown aerial rootlets that give a fuzzy, "hairy rope" look. Leaves are often glossy and can turn bright red or orange in fall, and small greenish flowers give way to clusters of waxy, whitish to cream berries.
Where it grows
Poison ivy thrives in disturbed soil, woodland edges, fencerows, hedgerows, roadsides, stream banks, and neglected corners of lawns and gardens, tolerating both sun and shade. It spreads by seed, which birds readily eat and scatter, and also creeps outward by underground rhizomes and above-ground runners that root as they go. Growth is most active from spring through late summer, with the plant dying back to woody stems and roots over winter.
Why it is a problem
The main problem is human health: contact with any part of the plant, including bare winter stems and roots, can trigger a painful, blistering rash, and the oil can linger on tools, gloves, clothing, and pet fur. It climbs and can shade or girdle desirable shrubs and young trees, and its rhizomes and bird-dispersed seed let a single plant colonize a large area over time. Never burn it, because the smoke can carry urushiol and cause serious harm if inhaled.
How to manage it
Manage it first through prevention: scout garden edges and fencerows regularly and remove young plants before they establish, since small seedlings are far easier to pull. When hand pulling or digging, cover skin fully with long sleeves, long pants, and waterproof gloves, remove as much of the root and rhizome as possible, and promptly wash skin, tools, and clothing to break down the oil. Repeated close mowing or cutting of ground-level plants, followed by smothering with heavy mulch, cardboard, or landscape fabric, starves the roots over time, and maintaining dense, healthy turf and vigorous plantings leaves little bare ground for seedlings to take hold. Bag and dispose of pulled material in the trash rather than composting or burning it.
Commonly confused with
It is commonly confused with Virginia creeper, which usually has five leaflets, and with boxelder seedlings and fragrant sumac, which can also show three leaflets but lack the long-stalked middle leaflet and hairy climbing vines of poison ivy.
General guidance for US lawns and gardens, focused on prevention and non-chemical control. For a confirmed identification and options specific to your area, contact your local Cooperative Extension office. Page updated Aug 4, 2026.