Have you ever gone on a hike, only to later discover an angry blister on your ankle? If the blister transformed into a dark purple blotch, chances are you came into contact with wild parsnip. The discoloration can last for a year or longer—probably not the kind of memento you want from a carefree trek in the countryside.
Wild parsnip was once domesticated, but it escaped cultivation and now is a familiar sight along our mountain roadways. In its first year, the plant forms a rosette of leaves and a tasty taproot. It’s difficult to identify at that early stage. In its second year, the parsnip produces a 5-foot stem topped with small yellow flowers in umbrella-shaped clusters. In this easily identifiable stage, the taproot has become tough and inedible.
Can you harvest wild parsnip as food that first year? You certainly could, but it would be safer to eat the roots of plants you’ve grown from seed so that you know for sure you’re not getting hemlock. Yes, the plant that was used to kill Socrates is related to parsnip. When it’s in bloom, it’s easy enough to tell the difference since hemlock has white flowers and is taller. Foraging books shy away from recommending a meal of wild parsnip since it would be dreadfully—fatally—easy to confuse the two plants in their rosette stage.
In addition to being an invasive European plant that crowds out native species, wild parsnip can cause a world of hurt. The issue is the sap. It’s phototoxic, meaning it causes irritation when exposed to sunlight. If you were to handle the leaves and shoots of a parsnip at dusk and take a shower before daylight, no problem. But if some of the sap gets on your skin and then sunlight hits it, you would develop a case of phytophotodermatitis. Phyto = plant, photo = light, and we all know what dermatitis is: the burning blisters and long-term discoloration previously mentioned.
Pollinators love the flowers and birds love the seed, ensuring the plant’s widespread dispersal. Black swallowtail butterflies are also called the parsnip swallowtail, though they lay their eggs on a variety of plants in the related carrot family, including Queen Anne’s Lace. Much like the monarch’s relationship to milkweed, the parsnip swallowtail caterpillar absorbs toxins from host plants, rendering it unpalatable to most birds.
So how do you rid your property of wild parsnip? With patience. Ridding yourself of the invader is a multi-year endeavor.
It’s best to ignore the plant while it’s in full bloom and the sap is running freely. Enjoy the beautiful yellow flowers, the visits from pollinators, the gorgeous swallowtails. Around the end of August, the stalk dries up and the yellow umbels evolve into ugly brown seed heads. Now is the time to make your move.
Although the dried stalk poses little risk, next year’s rosettes may lurk nearby, full of sap and ready to do harm. Therefore, you’ll want to adorn yourself with long sleeves, long pants, and heavy-duty gloves. For extra protection, perform the task as the sun is setting.
Grab hold of the stalk and pull hard, yanking up the roots. Try not to let the seeds shake loose, as they can persist in the soil for years. Stuff the uprooted plants seedhead-first into a large black garbage bag, and move on to the next plant. Repeat until the bag is full.
The next day, set the bag out in full sun, allowing the heat to kill the seeds. It’s best not to burn the stalks as any lingering sap could fill the air with caustic smoke. Throw the plants out with the garbage. The composting facility at the Delaware County Solid Waste Management Facility will render all organic material into a rich soil amendment.
And next spring, when you see those yellow umbels taunting you, dancing on their tall stalks, relax and enjoy the butterflies. Just remember to pounce around Labor Day.
Photo of Parsnip in bloom by Skogkatten at English Wikipedia, CC BY-SA 4.0