2 June 2013
Long ago I learned, “Look but don’t touch.” This is a good rule of thumb when you’re not sure of what you’re looking at outdoors.
Yesterday I attended the Wissahickon Nature Club’s annual picnic at Mingo Creek County Park. At Wissahickon we’re all curious about nature. Some know birds best, some know plants, others know insects, so our outings are really informative. We examine everything, we teach each other, we look up the mysteries, and we all learn something.
Yesterday I learned about cow parsnip, a large plant that I had largely ignored. Here I am standing next to it. Notice that I’m not touching it. That’s a good thing if you’re not sure what it is!
Cow Parsnip (Heracleum maximum) is a native member of the parsley family. Though it’s a good plant and was used medicinally by Native Americans, it looks a lot like giant hogweed (Heracleum mantegazzianum), an invasive plant from Eurasia that’s so toxic it causes nasty skin rashes if you merely brush against it. With so many botanists in the group I knew this plant was safe.
The umbels of cow parsnip and giant hogweed look similar to the untrained eye. The flower is large and pretty.
The real difference between the good plant and the bad one is that the stems and sheaths of cow parsnip are green.
This green sheath is good (cow parsnip). The bad one, giant hogweed, has purple splotches on its stem and sheaths and thick hairs at the leaf joint (but who wants to get that close!). Interestingly, poison hemlock, another bad member of the parsley family, also has purple splotches on its stem.
Rule of thumb in this case: green is good, purple is bad.
But the real rule of thumb is Look But Don’t Touch.
…which explains why I’m overdressed on a hot day. I always wear long pants, long sleeves, a hat, and sunscreen outdoors. You can’t see my ankles but my socks are pulled over my pant legs to keep out ticks. This outfit saves me a lot of itchy aggravation later.
We may look odd, but ask us about cow parsnip and we’ll tell you, “This one is OK.”
p.s. See the Comments for further discussion!
(photos by Dianne Machesney)
Being native may not mean that it is safe. The Washington State invasive species website (http://www.invasivespecies.wa.gov/priorities/hogweed.shtml) states that “Please note that cow parsnip sap also may cause burns or blisters.”
Interesting, Bill. The link you provide goes to a page about Giant Hogweed. Perhaps people out west also call hogweed “cow parsnip.” Or the variety out west is different than ours. Or some people react to cow parsnip anyway. On the other hand, it doesn’t make sense that Native Americans would use cow parsnip as a poultice to relieve skin problems if it was toxic, so some of it must be OK. In any case, I didn’t touch it.
Cow Parsnip is quite common in the West from the sea-level coast to high mountain meadows – mors so than in Pennsylvania.
Native Americans used many things that I won’t use. Just because someone says that Native Americans used something is no assurance that it is safe enough to me to use.
Giant Hogweed, Heracleum mantegazzianum comes from the Caucasus Mountains.
is designated as a federal noxious weed. The sap can cause severe blisters which can leave scars.
Cow parsnip, Heracleum lanatum is not on the noxious list. It is native and it’s sap is much milder. It could cause a rash on a sensitive person but generally there aren’t adverse reactions like the hogweed produces.
Cow parsnip is reported to have medicinal properties and was once used for treating epilepsy according to PA Dept. of Agriculture literature.
Thanks for the info, Dianne.
I was amazed to read on Wikipedia that “Perhaps the most common use [of Cow Parsnip] was to make poultices to be applied to bruises or sores. In addition, the young stalks and leaf stems — before the plant reaches maturity — were widely used for food with the outer skin peeled off giving a sweetish flavor. The dried stems were also used as drinking straws for the old or infirm, and to make flutes for children.”
This sounded very non-toxic to me.
i’ve seen cow parsnip 7 to 8 feet high, growing in optimal conditions along the loyalhanna creek in latrobe. poison hemlock grows profusely in places along the creek, in places along the flood control rip rap on the creek bank in downtown latrobe. the hemlock also grows profusely along a wooded roadside in our neighborhood, and some cow parsnip but not nearly as populous as the p. hemlock.
There’s a big patch of poison hemlock on my street, Tim. I think it smells ugly though some people say it smells like popcorn. Ick. I don’t know how it got there but it’s not going to leave on its own…
A casual observation. It appears to me that,in recent years, poison hemlock has become noticeably more prolific,especially along roadways. Poison hemlock stands…… by the mile! Makes me wonder if it has developed a resistance to roadside herbicide sprays.
When does the club meet for walks? I would love to attend.
Justin, I’ll put you in touch with Susanne Varley who has the schedule and directions to the outings. The next outing is tomorrow, Friday June 7, to Buzzard Swamp.
Thanks!