Wild parsnip near Allen Brook School. – Photo by Chapin Kaynor
By Chapin Kaynor
Special to the Observer
Wild — or “poison” — parsnip is the tall yellow-flowered plant along roadways and in fields, especially those that are untended, disturbed or moist. It is from the same family as vegetable parsnip, carrots and Queen Anne’s lace, and its flowers look a lot like yellow Queen Anne’s lace.
Some websites describe the flowering stalks as up to 4 or 5 feet, but we have plants up to 8 feet tall in Williston.
Unlike poison ivy, whose irritant is on the outside of its leaves, the “poison” of parsnip is in its sap. It causes rash, blisters and chemical burns with scarring that can last for several years. It is phototoxic, which means the sap does not cause this reaction until activated by ultraviolet light.
If you get sap on your skin, the Vermont Health Department advises: wash your skin thoroughly with soap and water as soon as possible; protect your exposed skin from sunlight for at least 48 hours; if you experience a skin reaction, call your health care provider.
I would add this: learn to identify the plant, including its rosettes. Teach your friends and family, too; wear clothing to protect your skin when around it (e.g. hiking); if you think you got some sap on you, cover that area with anything you can so sunlight can’t reach it until you get to where you can wash.
The people who have the worst experience are those who weed-whack it while wearing shorts and those who pick it for a bouquet. A friend of mine loaded a hay wagon bare-chested not knowing there was some parsnip baled in with the hay and he had terrible burns.
Parsnip is a biennial with rosettes the first year that store energy in the root to produce the tall flowering stalk the second year. Summertime brush-hogging and roadside mowing tend to spread seeds and expose the rosettes to more sun so they grow stronger than if they were competing with tall vegetation. Control requires careful pulling, tarping or regular mowing for several years since seeds remain viable in the soil for five or six years.
It is good to avoid poison parsnip, but if you must go near it, remember that sap on your skin is the primary danger, so brushing past healthy plants, especially with clothing, is unlikely to cause issues. If you undertake pulling it, know how to protect yourself and do it on cloudy days or in the early morning or late evening when sunlight won’t reach your skin.
Chapin Kaynor is a naturalist and conservation volunteer from Williston.