One of California's most beautiful wildlife plants is also one of the most hated natives: poison oak.
Few native plants can match the vibrant fall color, adaptability, and wildlife value of this shrub, groundcover, and thicket-former. It's one of the most effective barrier plants, but best used away from paths and well-used parts of the garden. Its signature “leaves of three” come in a delightful range of shapes.
But if you haven't heeded the rest of the childhood rhyme – “let it be” – your skin may bear reminders of the encounter for days or weeks. And, of course, the bare branches, the white berries, and smoke from burning branches are toxic to humans as well.
Knowing how to deal with poison oak is one of the most useful skills for a native gardener.
I've encountered poison oak mostly in wilder gardens and along hiking trails. A few years ago, wearing gloves and a long-sleeved shirt, I got a mild case of poison oak on my upper arm. That's how I learned urushiol, the allergenic oil, can wick through sweaty clothing.
I didn't get any poison oak on my wrists, which were exposed between gloves and sleeve, because I routinely swab them with rubbing alcohol after I finish working near poison oak. If you haven't used one of the products that claims to create a barrier, this is the best way to avoid a poison oak reaction: wipe the skin gently with an alcohol-drenched cloth at the end of a work day.
That's because urushiol begins to bond with the skin within 5 to 10 minutes after contact, but gently wiping the skin with a cloth drenched in rubbing alcohol can leach the urushiol out of the skin for up to 4 to 6 hours after contact, according to Susan Carol Hauser in a wonderful little book, “Nature's Revenge: The secrets of poison ivy, poison oak, poison sumac, and their remedies.”
It's a delicate balancing act: the urushiol is soluble in alcohol, but alcohol is easily absorbed into the skin. So you have to make sure to use enough alcohol to wash away the dissolved urushiol while being careful not to rub it back into the skin.
According to Hauser, copious amounts of water can also dilute the oil, but normal amounts of water, packaged alcohol wipes, or soap (if used without lots of water) can spread the oil. Avoid hot water, which opens the pores and makes the skin more vulnerable.
Once a rash appears, the urushiol is gone. It has been chemically changed and therefore cannot be removed (or spread). The rash is your immune system's reaction. The oil can, however, remain on your clothes and shoes, so wash them to avoid spreading it.
For severe cases, doctors prescribe corticosteroids, which interrupt the allergic process.
In milder cases, gentle home remedies for itching include cool or tepid compresses of plain water or a paste of baking soda or oatmeal. My cousin Barbara, who battles poison ivy in her Virginia backyard, uses a paste of epsom salts (3 teaspoons per teaspoon of water) to relieve the itching for hours.
Tanya Kucak practices organic land care, specializing in natives and edibles. She studied horticulture at Foothill College and Merritt College.
© 2006 Tanya Kucak