Wild parsnip, an invasive species all over North Country, can burn you, experts warn
Saturday, July 27, 2013 - 8:22 am

By PAUL HETZLER

It's not unheard of for people to burn vegetables now and then, especially if you're as easily distracted as I am. I'll think, the spinach is boiling, but there's time to pop out to the garden for chives. Thirty minutes later I'll be pulling weeds when the smoke alarm indicates the spinach is “done.” Oops.

While it sounds absurd to think a vegetable might burn people, it does happen, and this is peak season for it. The burn is chemical in nature, and the vegetable is wild parsnip, an invasive species whose population has exploded in the past few years. Related to Queen Anne's lace, wild parsnip grows three to five feet tall, topped by yellow-green “umbrellas” of flowers which are about to set seed. It can be found in vacant lots as well as in yards and gardens, but because it's so effectively spread by mowing equipment, mile after mile of it can be seen along North Country roadsides.

The root of wild parsnip is in fact edible, but its sap, like that of giant hogweed, is “phytophototoxic.” The word may win you a Scrabble game, but it means wild parsnip sap on your skin reacts with sunlight to cause severe burns. And by severe I mean burns requiring medical attention and taking months to heal. Unlike poison ivy, merely brushing up against this plant won't cause symptoms, but when handling it, it’s wise to wear gloves and long sleeves anyway.

As everyone knows, when fighting zombies, you grab a shovel and aim for its head. The same with wild parsnip, except you aim for its feet. It has a taproot which is nearly impossible to pull out, but which is easily cut with a shovel. It's not necessary to get the whole root; just dig as deep as you can to sever the root, pry up and the plant will die. You don't even have to touch it.

If you’re hopelessly outnumbered by wild parsnips, at least mow them to keep them from making seeds while you muster some shovel-wielding townsfolk (pitchforks and torches are optional) to help you. But wear protective clothing when mowing wild parsnip, and unless you have a Level-A hazmat suit, don’t use a string trimmer on it. One small consolation is that once the sap is dry it poses no threat.

Glyphosate, the active ingredient in herbicides like Roundup, is effective against wild parsnip. Herbicide is most effective when used on first-year plants (“rosettes”), ones which have no flower stalk, in late summer or early fall. Spraying early in the season may only kill the top but not the root.

Years ago, I distinctly remember having burned some parsnips, so I hope none of this is my fault. I suggest everyone try not to burn any more vegetables, though, lest they all become vengeful.

Paul Hetzler is a forester and a horticulture and natural resources educator for Cornell Cooperative Extension of St. Lawrence County.

Photo by P. Hart, NYSDOT