OSKALOOSA, Iowa — It’s an unassuming roadside weed that looks a bit like a yellow Queen Ann’s Lace.

Wild parsnip — Pastinaca sativa — and the blistered rashes that are the result of coming in contact with the plant have been making headlines recently.

Conditions for wild parsnip and another weed, poison hemlock — Conium maculatum — have been “especially favorable,” according to a recent Iowa Department of Natural Resources release. They are both often found in ditches, pastures, field edges and other natural areas.

“Wild parsnip flowers primarily from May through July; poison hemlock flowers from May through August,” stated the DNR. The plant is usually 2-5 feet in height. “The flowers are small, predominantly yellow (occasionally white) and five-petaled, arranged in an umbrel spanning from 2-6 inches.”

Wild parsnip contains a substance called psoralen, which is an irritant when it comes in contact with skin.

“The chemical reaction can be severe to mild depending on the person and exposure,” said Mahaska Health Partnership Public Health Coordinator Patty Malloy, RN. “Reaction can be a brown-color discoloration of the skin to burns that look like a sunburn, or more severe with blisters.”

If you think you may have come in contact with wild parsnip, your first move should be to get out of the sun.

“The sap reacts with sunlight, so if you have come in contact with wild parsnip, cover your skin to prevent the UV rays and sap from having a chemical reaction,” said Malloy. “The oil on your skin or clothes can be spread by itching and rubbing as well as remaining in the sunlight, making the reaction more intense.”

Skin should be thoroughly cleansed with soap and water as soon as possible after exposure to wild parsnip, and avoid exposing affected area to sunlight for 48 hours. Be sure to immediately wash clothes that might have sap on it as well. Malloy suggests treating the burning pain with cool compresses and over-the-counter pain medications as needed.

“Do not break open the blisters, as they keep the area covered and reduce the chances for infection. Keep the skin as clean and dry as possible and use antibiotic cream if needed,” she said, also noting that anyone who experiences symptoms such as severe pain, fever, redness or any drainage from the skin, should consult a doctor. 

Keep an eye on pets, as they could have similar reactions if exposed to wild parsnip.

As far as the wild parsnip’s relative, poison hemlock, the Iowa DNR states that “all parts of the poison hemlock plant are highly toxic to humans and animals and may result in death if ingested. Livestock poisoning usually occurs from the presence of poison hemlock in hay or when pastures are overgrazed and other sources of food have been depleted.”

Repeated mowing, pulling of the plants, digging up the root crowns, as well as chemical options can be effective control methods, according to the Iowa DNR. Just be sure to keep your skin covered.

Holland writes for the Iowa, Oskaloosa Herald.