Cow Parsnip

2017 February 4
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These were photographed on July 5, 2016. They were growing in the ditch alongside our road, where the ground is consistently moist. The photo doesn’t fully do justice to the size of the plants, they were around four to five feet tall.


These are Cow Parsnips, Heracleum maximum. It is one of the hogweeds in the genus Heracleum, and the only one of the hogweeds that is actually native to North America[1]

These are in the Carrot family, but instead of thin leaves like carrots have, these have broad, palmate leaves that look more like mega-sized parsley.


You want to be careful handling these plants, because they secrete a clear fluid that contains Furanocoumarins. Once these chemicals get on your skin, the are activated by the ultraviolet light in sunlight to cause a fairly unpleasant dermatitis.


The flower heads are similar to those of other members of the carrot family, resembling an umbrella made of separate small flowers. Nectar-feeding insects like them – I think that’s a European Skipper on this next picture.



Since they are related to the Queen Anne’s Lace (wild carrot) that we have around here in some profusion, it is not too surprising that they are fed on by some of the same insects. For example, this flower head was all webbed up by an insect


that turned out to be a Carrot-Seed Caterpillar, Sitochroa palealis.

There were a number of these caterpillars, and they all looked bigger and fatter than the ones I see on the wild carrots. Probably because the Cow Parsnip has really big, nutritious seeds. These seeds (which weren’t quite ripe yet) were each close to a centimeter across (about the size of the fingernail on my little finger).


Supposedly the young stalks are edible if you peel them, and once dried the old stalks are usable as drinking straws or for making children’s flutes.

[1] A few years back, our local paper ran an article about a particularly noxious invasive species, the “Giant Hogweed”, Heracleum mantegazzianum, that had been starting to move into this area. The article ended with an exhortation to report any sightings to the Department of Natural Resources. And then, we walked down the hill, and spotted these Cow Parsnips, which look strikingly similar (the main visible difference is that the Giant Hogweed is about 2-3 times taller). So, not knowing any better, we left a message on the DNR answering machine about it. And then, after looking into it a bit more, found that what we actually had was a native species that was of no special concern, so we called them back to apologize.

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