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It seems like cow parsnip is everywhere – but it could be so much worse

  • Author: Jeff Lowenfels
    | Alaska gardening
  • Updated: July 27, 2018
  • Published July 27, 2018

(Bob Hallinen / ADN)

Lots of readers have been asking about cow parsnip after seeing a couple of articles repeatedly splash across all their news feeds this month. The first was an article was about a gentleman who suffered severe burns from an encounter with a "giant cow parsnip." The pictures showed a plant with flowers and leaves that looked just like the cow parsnip that grows all over Alaska. The plant, however, was much bigger, twice the size of the guy standing in front of it.

Then, last week, a second viral internet news article detailed the story of a Vermont woman who went to the hospital with blister-burns from a run-in with what was described as "wild" parsnip. The plant had flowers just like our parsnip, only they were a much nicer yellow than our off-white ones. The baseball-sized blister was really, really painful looking and equally ugly.

Relax. Somewhat. Both of those reports involved plants that look like, but are not the same as our own "cow parsnip," aka Heracleum maximum (sometimes H. "lanatum"). Not sure what it looks like? You see it in every meadow around, 4- to 6-foot plants with white, umbel flowers that have been in bloom for the better part of the month and are now going to seed. It has spread to the point that most homeowners have some on their property. (Of interest is that there are male and female flowers on each plant).

In the case of the the man with the burns, that plant was an invasive known as Heracleum mantegazzianum. This is a plant introduced into England in the 1800s for ornamental and curiosity value and is now starting to spread in the U.S., particularly the East Coast. It is twice the size of our "cow parsnip." Heaven help us, please don't import it here.

The Vermont plant is botanically known as Pastinaca sativa. These have yellow flowers and were also introduced. You can see from the pictures (which will be floating around the internet for another few weeks), that its colored flowers made someone think it was a nice alternative to the plain old regular parsnip plants. Big mistake.

No, ours is the only native plant in the bunch. It is sometimes even referred to as "American" cow parsnip. It does spread like crazy and I consider it invasive. It surely isn't something you would want to collect seeds from and then plant, unless you wanted it to take over and obliterate your lawn.

Anyhow, all three of these plants will cause phytophotodermatitis, aka skin burns, when exposed to ultraviolet light (i.e. sunlight). This reaction is due to chemicals, obviously, in the leaves and stalks. That is the bad news.

The good news is that Heracleum maximum sap isn't as strong as the saps of the other two. You will get far less of a burn, usually described as a rash, should you encounter it. Still, Alaskans need to be very careful around these plants, especially when mowing the lawn or weedeating around the yard. Teach kids about them, too. I remember reading Alaska reports of children getting blisters from sitting on cut stalks.

Oddly enough, these plants had lots of uses. Dried stems were used as straws. Young stems, sans the "bark," were eaten and, as a matter of fact, still are by those who claim they are quite a delicacy and who know how to handle the young plants.

So, there you have the other part of the story of blistering cow parsnips. These news items illustrate two important points for the Alaskan gardener. First, we still have to recognize things are different here. Not everything we read from the Lower 48 applies.

Second, these stories show the dark side of introducing non-native plants into an a new territory. Not only can new plants become invasive, they can even pose a real danger to life, or in this case, limbs. As I have noted frequently of late, it really is time for the Alaskan gardener to consider the damage we have already done and make sure we don't cause anything new. Think about it while you exhale, because all those plants you thought were highly poisonous aren't as strong as either yellow or giant cow parsnip.

Jeff's Alaska garden calendar:

Annual City Garden Tour: It is here! The annual, self-guided Anchorage Garden Club Home Garden Tour. Do not miss this. It is 12-5 p.m. Sunday, July 29: Six Anchorage gardens are open for the tour.

The gardens of greater Eagle River will be on July 28. Another tour of home gardens!

Here is the information you need:

Wine in the Woods: Mark your calendars for 6:30-9:30 p.m., Thursday, Aug. 2. There is going to be a delightful evening of wine and plants at the Alaska Botanical Garden. Following on the success of Beer In The Garden, you won't want to miss this fun evening. $65 for a wine tasting ticket ($75 on the day of event), $30 for designated drivers.

Potatoes: Too early even for new potatoes. Continue to surround stems with leaves or soil.

Peas: Give them a chance! Start harvesting

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