Scientific Name: Toxicodendron diversilobum
Poison oak is identified by 1-inch to 3-inch long leaflets with two to seven deep lobes resembling oak leaves. Lateral leaflets appear without stalks on viny stems about 3 to 4 feet tall. Like poison ivy, leaflets are grouped three per leaf, and flowers are yellowish. Poison oak is found throughout the southeast and along the Pacific coast in the United States.
Follow the same recommendations for control of poison oak and poison ivy. Young plants less than a foot tall with only a single stem can be physically removed with little difficulty, especially in the spring when the ground is soft. Gloves should be worn to avoid allergic reaction. No part of the plant should contact skin. Burning is dangerous. Poison oak rarely infests mowed turfgrass areas, but could become a problem in infrequently mowed golf course roughs, as well as in fence lines and along rock walls. Both poison ivy and poison oak are commonly found in rights-of-way and other such minimally managed sites.
Large, well-established infestations can be a problem to remove either mechanically or chemically. A series of post-emergence broadleaf herbicide foliar treatments may be required to conquer a large infestation of poison ivy or poison oak. Vines which have become well-established in trees can be practically impossible to eradicate without herbicide damage to the tree. In these situations, an ester herbicide labeled for mixing with oil for a basal stem treatment may be required. For optimum foliar control, make your herbicide application to poison oak that is actively growing and in the first trifoliate leaf to flower stage of growth.
Weed Photos: Courtesy of Dr. Lambert McCartey. Clemson University. Clemson, SC.