Wild parsnip: not your garden variety weed

This weed is not worth messing with because its sap can cause festering blisters capable of leaving permanent scars

There’s a nasty weed on the loose in Saskatchewan.

And if you come across it, your best course of action is to steer clear and call the authorities.

Wild parsnip has been around since at least the 1920s, but lately it’s been showing up in more locations across the province.

If you stumble upon the plant unknowingly, the results can be debilitating.

The plant’s sap can cause festering blisters capable of leaving permanent scars.

“As is the case with other members of the carrot family, the wild parsnip is very good at defending itself,” said Clark Brenzil, provincial weed control specialist with Saskatchewan Agriculture.

“It has a sap in it — similar to cow parsnip and giant hogweed — and when you get that sap on your skin and then you get exposed to the sun, you’ll get the worst sunburn you’ve ever had.

“Essentially, what happens is that the sap has compounds in it that reduce your skin’s defences against the UV rays of the sun.”

Wild parsnip is actually the same plant species as the parsnips that some people grow in their gardens, Brenzil said.

The difference is that common garden parsnip has been selected for human cultivation and its straight edible root.

Nonetheless, exposure to the compounds in cultivated parsnip can have a similar effect on exposed skin.

“Most people are blissfully unaware that the common garden parsnip can have the same effect.”

Cow parsnip, a close relative that’s native to Saskatchewan, can also cause painful burns and blistering.

Visually, cow parsnip and wild parsnip look very similar, but the flowers on cow parsnip are white, whereas the flowers on wild parsnip are yellow.

Both have an appearance similar to a dill plant with a distinctive umbel flower structure.

Umbel flowers look like a bit like an umbrella.

Stalks that come off the stem to create the flower structure all originate from the same point on the stem.

“Probably a good rule of thumb in general is to give members of the carrot family a reasonably wide berth,” Brenzil said.

In other words, if you aren’t familiar with the plant and it has an umbel-shaped flower structure, stay away.

According to Brenzil, wild parsnip has been growing in Saskatchewan for a century or longer.

But more recently, it been showing up in areas where it hasn’t been seen before.

“It is expanding its range a bit,” Brenzil said.

“It’s showing up in areas that it hasn’t been seen before, in any particular numbers, but there are a few hotspots of it that have been around for a long, long time.”

Cow parsnip, the native cousin, is a large plant that can grow up to eight feet tall.

“Along with other members of the carrot family, you generally find it in areas that have been fairly wet, in forest areas … or near streams and riverbanks,” Brenzil said.

“It has a fairly large leaf that can be about a foot across, maybe a foot and a half sometimes.”

Both cow parsnip and wild parsnip are designated as noxious weeds in the federal Weeds Seeds Order.

In Saskatchewan, the weeds are listed under the province’s Noxious Weeds Act, meaning rural municipalities, weed control officers and landowners should take steps to control their spread.

“The whole goal of the Noxious Weeds Act is to manage and prevent spread, so they should be on top of any new populations,” Brenzil said.

Anette Ellert, programs manager at the Saskatchewan Association of Rural Municipalities said funding for weed control is available to eligible Saskatchewan RMs and First Nations groups that apply for assistance through the Invasive Plant Control Program.

The program reimburses eligible groups for up to 50 percent of the costs of pre-approved herbicides and application expenses for controlling prohibited weeds.

In addition, applicants can apply for up to 50 percent of the cost of herbicides used to control noxious weeds.

Total funding through the program in 2018-19 is $500,000, down from $800,000 in 2017-18.

Program details can be viewed online at sarm.ca/programs/administered-programs/ag-programs/cap-ipcp.

“There’s limited funding available so (the amount that each applicant receives) depends on the number of applications that are received,” Ellert said.

Funding through the program was not fully allocated in 2017-18, she added.

The deadline to apply is Oct. 31.

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  • Clark Brenzil, PAg.

    A couple of article corrections:
    – blisters are not “festering” which implies infected. As with other burns, blisters can develop that are fluid filled but not infected unless burst and not kept clean
    – wild parsnip is regulated as a noxious weed because it is introduced to the continent from Europe and spreads aggressively if not managed; similar to other regulated weeds like leafy spurge or scentless chamomile. Cow parsnip is not regulated because it is a native plant to Saskatchewan and therefore ubiquitous.
    – the root of wild parsnip is edible. The only way it differs from domestic garden parsnip is root shape.
    – cow parsnip is not regulated by the Weed Seeds Order of the Canada Seeds Act

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