14 common garden invaders and the best ways to control them
Poison ivy looks similar; it's common east of the Rockies and also grows in eastern Oregon and eastern Washington. Usually found in shady areas and at the edges of woodlands, it sprawls along the ground until it finds something to climb, then becomes a vine.
A resin on both poison oak and poison ivy causes severe contact dermatitis in most people. Control the both with an appropriately labeled herbicide, such as glyphosate (be sure to avoid getting these chemicals on other plants).