Yard MD blog: DANGER! Beware of this plant

One of the most dangerous plants found in our area, wild parsnip is now in full bloom and its invasive nature can be seen all along area roadsides, highways and ditches. Avoid getting the plant’s juices on your skin as severe burning and rash may result within 24-48 hours.
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Rob Zimmer/Post-Crescent Media.
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You may have caught one of my earlier blogs during Invasive Species Awareness month in June on dangerous wild parsnip.

This plant is extremely dangerous and should be avoided, especially when in bloom, as it is now across east-central Wisconsin. If you get any of the plant's juices on your skin, it will result in a severe burn in 24 to 48 hours after exposure to ultraviolet light. This does not just mean 'sunlight.' UV light is just as prevalent on cloudy days.

You will not notice anything immediately, but a rash and burning will begin to develop on most exposed areas within a day or two. This burning can be so severe as to leave permanent scars. A simple internet search of wild parsnip burns will convince you.

This reaction is known as "phyto-photo-dermatitis." Simply put, it means that plant produces a rash or burning when exposed to the skin and ultraviolet light. The burning effect takes time, but as it develops, it destroys skin tissue, often creating permanent scarring.

When the plant first became widespread in our state, the bizarre burning and blistering caused by wild parsnip was a mystery to physicians and nurses. Soon, however, the culprit was identified and the word began to spread about the dangers of this plant.

This plant spreads rapidly and forms large colonies, and is now in full bloom all across our area, mainly in meadows and along grassy ditches. You will notice it along many local highways and roadsides throughout our area, with its large, umbrella-shaped blooms in golden yellow and tall, celery or dill-like form.

Like most invasive plants, there is no easy fix once wild parsnip moves in. If you have it, repeated cutting and treatment of the canes with Roundup or similar herbicide is the best answer. This is not a one-time chore. It will need to be done week after week throughout the growing season, into fall, and likely in subsequent seasons as well. That's why they call it "invasive."

If at all possible, do not allow the plant to flower and go to seed. Mow repeatedly and often.

Wild parsnip is a close relative to the much-hyped giant hogweed. The effects of wild parsnip are just as severe, and wild parsnip is an even greater threat since it is already well-established in our state. Giant hogweed is present in just a few small isolated patches.

Wild parsnip is here to stay. The plant is well-established in all 72 counties of the state and, like most invasives, will never be fully eradicated. It is up to us to be aware of the plant, the dangers it poses and to avoid it, as well as educate others to do the same.

— Rob Zimmer: 920-419-3734, yardmd@postcrescent.com

Yard MD Rob Zimmer explains the how the invasive species, Japanese Knotweed, can crowd out other plants once it gets a hold in your landscaping. (June 30, 2014)
Jim Rosandick and Rob Zimmer/Post-Crescent Media