Poison ivy grows all over the Hudson Highlands. You'll find wily poison ivy growing up trees as a vine, as groundcover, or as a shrub. "Every part of the plant contains an oil called urushiol that inflames skin and results in painfully itchy blisters and rashes," explains the New York State Department of Transportation in its helpful guide to poison ivy.

Leaves hang from the stem in groups of three. So remember the rhyme leaves of three, beware of me. Tricky poison ivy changes its appearance in different seasons — and it sports leaves of different shapes. The New York City Department of Health produced the handy guide below to help individuals identify the leaf shapes and seasonal appearances of poison ivy. Additionally, this interactive poison ivy quiz helps you to learn to distinguish between poison ivy and other similar-looking plants growing next to it.

If you touch poison ivy during a hike, wash skin exposed to urushiol oil with soap, lukewarm water, and a wash cloth. In the video above, Dr. Jim Brauker demonstrates how to wash off urushiol by using vigorous friction — and by washing the area at least three times. The American Academy of Dermatology offers tips for managing and treating rashes caused by poison ivy.