Poison ivy, oak and sumac: ecological value, sinister beauty
Like some nefarious version of the three sisters, poison ivy, poison oak and poison sumac have long loomed in the minds of every gardener and outdoor adventurer. These species, containing the urushiol responsible for irritating our skin, have been explored for medicinal properties, cultivated for horticultural collections and celebrated with festivals for years.
Poison ivy, found in abundance regionally, was first described by John Smith in 1624. In 1784, American naturalist William Bartram began shipping botanical specimens from the New World to British plant collectors. Both poison ivy and poison sumac were sent overseas, and by 1804 they were thriving in the gardens of Josephine Bonaparte, in artist depictions and medical publications. Antiquated medicinal uses for poison ivy can be found in “A History of Herbal” by Richard LeStrange, including as a treatment for rheumatism, ringworm, persistent herpetic eruptions and even paralysis or stiffness.
With nearly 70% of the population sensitized to urushiol, according to Aaron Gladman’s publication in the journal of “Wilderness and Environmental Medicine,” contact dermatitis caused by poison ivy, oak and sumac are the leading cause of allergic dermatitis in North America, affecting up to 50 million people each year. Up to 10% of the U.S. Forest Service’s losttime claims each year are due to the effects of urushiol, the agency reports.
This week I caught up with Chesapeake resident Eric Terry when I caught wind of his recent exposure to poison sumac. Terry was doing yard work in Troutman, N.C., and was made aware of the poison sumac growing in his mother’s yard. Because he had never been affected by poison ivy before, Terry assumed he was tolerant to its infamous skin-irritating compounds. “I saw it growing up from the bushes but just thought it would be fine and took a hedger to it,” he said, “I’m a believer now.”
At one point during the work session his wife clipped her finger with the shears and needed minor first aid. At that point, Terry went inside to wash his hands and arms with cold water and Dawn dish soap, which he believes helped limit the severity of his reaction. Gladman’s publication states that although urushiol degrades easily with soap and water, it must be washed off quickly to remove clinically significant amounts. Up to half the urushiol is absorbed by the skin after just 10 minutes.
Despite the washing, within two days Terry began seeing red bumps appear and said by the fourth day his forearms, ankles and feet had erupted with a fiery red weeping rash. He described incessant itching and burning, listing a plenitude of remedies explored. Only two provided any relief — cold water and topical CBD oil.
Thankfully, because urushiol is so irritating, treatments and preventatives have been explored. Native Americans used our native jewelweed, Impatiens capensis. Its effectiveness has been explored in clinical trials published in the Journal of Ethnopharmacology by Vicki Abram Motz, et al. The saponins, or soap-like components, in jewelweed are likely what help reduce rash development. Those who are severely affected by urushiol can take heart knowing the University of Mississippi and Hapten Sciences have been issued their fourth patent on vaccine technology to prevent reactions to poison ivy, oak and sumac.
Each year in the fall Columbia, California, hosts the Poison Oak Festival, which includes an exhibition of leaf arrangements, accessories and recipes. It’s in the fall, when leaves turn bright red, that they are most enriched with urushiol. But despite their vexing properties, the three sisters of the Toxicodendron genus are native plants that have ecological value and sinister beauty.
In Full Bloom is a weekly feature from Allissa Bunner that focuses on sustainable gardening, environmental stewardship and related community news and initiatives. Bunner is a Norfolk resident who is passionate about plants — especially natives — and enjoys growing things from seed. She can be reached at acbinfullbloom@gmail.com.