Poison ivy
In Minnesota, poison ivy grows as a ground cover or a thin, low shrub, ranging from 6 inches tall to 3 feet tall. Leaves are compound with three leaflets. A common rhyme associated with the plant rings “leaves-of-three, let-it-be.” Spring leaves emerge shiny, tinted reddish-brown, and later become a matt-green when fully expanded. Leaflet edges have no teeth, a few teeth, or several large teeth. A key identifying feature of the leaf is the center leaflet extended by a longer stem than the two lateral leaflets. Poison ivy’s fall color is vibrant, ranging from clear yellow to scarlet red. Its leaves fall in early autumn before most native plants, leaving bare woody, gray stems, sometimes with fruit.
Poison ivy fruits are berries about 3/16 inch in diameter. They’re light green in summer, turning creamy yellow in early autumn. They persist through fall and winter, when they become most visible. Poison ivy fruits are eaten by birds & animals who help spread the seed.
Poison ivy spreads to form patches by underground rhizomes (roots). It can move to new locations by seed, inside the fruit, which may fall to the ground or be eaten and transported
Urushiol (yoo-ROO-she-ol) is the “poison” oil found in poison Ivy, poison oak, and poison sumac. Poison oak does not grow in Minnesota. Poison sumac does, but is not too common and is usually found in swampy or low areas. Urushiol is found in the leaves, twigs, and roots of poison ivy, not the flowers. The oil causes contact dermatitis, including itching, blistering, and watering skin. The oil can vaporize when burned and oil droplets can land on skin or be inhaled. Urushiol in the lungs can require hospitalization
Are you in danger? Clinical trials have found that 85% of those tested are susceptible. Callused skin is not commonly affected, but soft skin is. Oil can be transferred to skin directly from the plant or indirectly from clothing, boots, tools and animal fur.
Prevent symptoms after contact with poison by washing affected skin thoroughly with cold soapy water ASAP. Relief for the insatiable itching that results from an undetected encounter, can be obtained with calamine lotion, hydrocortisone 5%, or prescription drugs.
“Leaves-of-three, let it be.” Poison ivy is not the only plant in the woods with compound, three-part leaves. Common natives that look very similar are: boxelder seedlings, wild raspberry, jack-in-the pulpit, tick trefoil, and hog pea-nut—all have compound three-part leaves.
