Camping, hiking and gardening in the summer provide opportunities to enjoy the local foliage. Poison oak has three leaflets per leaf. In autumn, these leaflets turn bright red. The leaves are shiny when the plant is young. Most people are allergic to the plant known by the botanical name Toxicodendron diversilobum.
Poison oak can cause a red rash and even painful, itchy blisters.
The plant can be difficult to eradicate, and people shouldn't take on this challenge without doing some research first. Valley Center resident Ronald E. Wheeler has been experimenting with ways to get rid of poison oak as part of his job. Since 1993 he has managed the Valley Center field station owned by Scotts, a pesticide firm, where new formulations of herbicides are tested. He said herbicide enters the plant through the leaves or bark and kills the poison oak when it reaches the roots. Wheeler said that herbicides containing triclopyr are absorbed by not only poison oak but also by trees.