Gerald L. Klingaman
Plant Common Name
Eastern Poison Ivy
Poison ivy is the bane of the American hiker, camper, gardener or general outdoors person. The whole plant is poisonous to the touch and induces a nasty skin rash that can be quite severe depending on the sensitivity of the person touching it. This North American native is a common, weedy, deciduous liana (woody vine) that can be found everywhere from moist or dry meadows, woodlands, roadsides or disturbed sites. Its stems produce clinging, aerial roots that help the vine ascend the tallest tree or creep along the ground as a poisonous groundcover. Some even become shrubby.
Poison ivy has three compound leaves, hence the warning, "leaves of three, let it be." The three oval leaflets are deep green, taper at the tips and have coarse, irregular teeth along the edges. When they emerge in spring they are often glossy bronze or burgundy red. In fall, they turn vivid shades of orange, yellow and red. Insignificant yellow-green flowers are produced in late spring followed by dull ivory berries that are eaten with gusto and spread by song and game birds. After the leaves fall, brown, erect stems (which are also poisonous to touch) can be seen. The aerial roots of vine specimens are dense and look like thick, clinging hairs.
Like most weeds, poison ivy will grow almost anywhere. It thrives in both full sun or shade and nearly any soil type that offers average to sharp drainage. Eradicating poison ivy should be done with caution and care. Its poisonous oils are just as potent when plants have been killed by herbicides or hand pulling. This plant should never be burned because the poison will become airborne in the smoke, which means poison ivy in the lungs—a very dangerous prospect. Composting is also not recommended. Really, the best thing to do is safely dispose of it in plastic far from where anyone can touch it.
The oils in the stems and foliage of poison ivy are what cause skin rashes. This allergy is only known to affect primates. Pets are generally unaffected but can transfer the oils to their unassuming human master. Many people are immune to poison ivy but become allergic later in life. For more information on the health concerns, visit http://www.ces.ncsu.edu/depts/hort/consumer/poison/Toxicra.htm .
AHS Heat Zone
9 - 1
USDA Hardiness Zone
3 - 9
Full Sun, Partial Sun, Partial Shade
1'-60' / 0.3m - 18.3m
2'-6' / 0.6m - 1.8m
North America, United States, Northeastern United States, Mid-Atlantic United States, Southeastern United States, North-Central United States, Central United States, South-Central United States, Texas, Canada, Mexico, Central America
Acidic, Neutral, Alkaline
Clay, Loam, Sand
Drought Tolerant, Average Water
Spring, Summer, Fall
Sharp or Has Thorns