Poison Oak in Open Space

Many areas throughout Sycamore Grove Park have poison oak. Even though most of these areas are far off the trails, it is still important to know how to identify poison oak and know what to do if you touch it.

Poison oak leaves of different colors, from greens to reds to yellows. — Poison oak leaves in identifiable clumps of three. Typical of poison oak in our area in the summer and early fall. This photo, “Poison oak” is copyright (c) 2005 keepps and made available under a Attribution-Noncommercial-Share Alike 2.0 license

Dense, leafless bush branches of poison oak in the late fall and winter. — In the fall and winter, poison oak appears as leafless bushes or vines and can be harder to identify. The leafless branches can still cause a reaction if you come in contact with it. Photo by Ranger Jay Manning.

Identification

Poison oak (Toxicodendron diversilobum), aka pacific poison oak, is native to western North America. Poison oak can grow in a variety of habitats including grasslands, scrublands, and forested areas. Although poison oak in the park often appears as a shrub, it can also grow as a climbing vine. The branches of poison oak are woody. A good rhyme to help identify poison oak is, “leaves of three, let it be”. This refers to the fact that poison oak leaves are usually arranged as a group of three leaflets. Poison oak leaves resemble the leaves from an oak tree, but these plants are part of the sumac family, not the oak family.

Poison oak contains urushiol. Urushiol is an oil-like substance found on branches, leaves, and berries of a poison oak plant. When a person’s skin comes in contact with urushiol, it can cause a rash, inflammation, and itchiness. With repeated exposure to poison oak, a person’s reaction may worsen. Although humans have a negative reaction to it, animals don’t react to urushiol. Many animals benefit from poison oak. Birds eat poison oak berries and eat insects that hide in poison oak. Some birds will also nest in poison oak shrubs because of how densely it grows. Also, mule deer and small mammals will eat poison oak leaves.

How to Prevent Contact with Poison Oak

Stay on trail.

We do our best to trim any poison oak from the trails in the park. If you stay on trail, it’s easier to avoid accidentally touching the plant.

Keep your dog on a leash.

Dogs are often not impacted by poison oak, but the oil can remain on their fur and cause a reaction in anyone who touches them. Wash your dog if you suspect they touched poison oak.

Be able to identify poison oak.

If you can identify it, you can avoid it or recognize if you have come into contact with poison oak to take steps to minimize or prevent a reaction.

What to do if You Touch Poison Oak

Immediately wash gently with cool water and a strong soap such as dish soap.

Make sure to wash with cool water, NOT hot water which could open your pores and could worsen you reaction. Wash gently to prevent from scrubbing the urushiol into your skin. Remember to wash under your fingernails to avoid repeated exposure.

Wash any clothes, surfaces, or objects that came in contact with the plant.

The oil from poison oak could remain on clothes or other surfaces for years if it’s not washed off.

Be aware that symptoms may not appear from 4 hours up to 2 weeks after exposure.

People who have had a rash from poison oak, ivy, or sumac before will likely develop symptoms before someone who has never had a rash from these plants.

Additional Information

Poison oak rashes will heal on their own. However, anti-itch creams and medications can help manage symptoms. The rash will only appear in areas that have touched plant oil; therefore, it cannot spread from person to person. Also, poison oak cannot be spread from one part of your body to another from scratching the rash. Although the rash may appear to be spreading, this is because your body may absorb the urushiol at different speeds, or you may have the plant oil trapped under your fingernails.