Poison hemlock invading our area
Weed just keeps spreading, but don’t confuse with QAL.
For several years I have been writing about a weed that is becoming quite prevalent around the Miami Valley. It seems that it just keeps spreading and no one is paying attention, except for gardeners and, I hope, readers of this column at the very least!
Poison hemlock has been on my radar for many years now, since a colleague of mine, Joe Boggs, Hamilton County Commercial Horticulture Educator, OSU Extension, wrote about it in the Buckeye Yard and Garden Line.
Typically I observe this growing in ditches and other disturbed areas and many times in masses. You are seeing it toward the end of its bloom right about now.
Don’t confuse it with Queen Anne’s Lace (QAL); I suspect many people think this is what they are seeing. Poison hemlock and QAL are in the same family and are both biennials, but there are a few distinct differences.
Poison hemlock blooms in late May into early June. QAL starts to bloom in mid- to late-July and August.
Both emerge in the spring the first year and form a basal rosette of leaves. Both send up flower stalks on the plant the second year. Both have white flowers. However, poison hemlock can grow up to 10 feet tall; QAL is only around three feet tall.
Poison hemlock stems lack hairs and have distinct purple splotches; QAL has a green stem with hairs.
Another problematic plant blooming now with similar characteristics is wild parsnip. This plant has yellow flowers and the foliage resembles celery foliage. I don’t tend to see as much of this around my area but perhaps you are seeing both poison hemlock and wild parsnip in fields together.
Why the big deal? For starters, the sap of poison hemlock is what killed Socrates. All parts of the plant are poisonous to mammals if ingested.
It’s likely that humans won’t ingest it, but I see this in and around hay fields, sometimes even getting into hay cuttings and consequently bales.
Wild parsnip can be worse for
humans because of a toxin called psoralen. Skin exposed to the sap of wild parsnip and then to the sun is subject to phytophotodermatitis. The result is burn-like symptoms, skin discoloration, and blisters.
Joe wrote another article recently on these plants in the Buckeye Yard and Garden online (http://bygl.osu.edu). I urge you to go to this blog and read more about these plants and see pictures to become more aware.
Our final session in the Grow Clark County Gardening Series will be held Wednesday, at 6:30 p.m. OSU
Extension Horticulture Program Assistant Kathy McConkey will present “Darn, I Wish I’d Known That!” Learn about things that if you had known before you started gardening, might have saved you time, money and plants.
Participants will be entered in a drawing for one of four $25 gift certificates to Siebenthaler’s Garden Center, our sponsor for this virtual program. Winners will be selected at the end of the webinar.
Pamela Corle-Bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her at bennett.27@ osu.edu.