Native Plants

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Monday - June 09, 2008

From: Hudson, OH
Region: Midwest
Topic: Poisonous Plants
Title: Poisonous plant in Ohio with hydrangea-like flower
Answered by: Nan Hampton

QUESTION:

Dear Mr. Smarty Plants, I was sure that I had read that there is a poisonous bush that is native to Ohio that has flowers something like a white hydrangea..or was it queen ann's lace? I believe the flowers could cause severe respiratory distress. Any ideas of what this shrub could be?

ANSWER:

Hydrangea spp. can be toxic (nausea, stomach pain, vomiting, sweating) but only if eaten in large quantities. Queen Anne's lace (Daucus carota) leaves cause skin irritation, but are edible if cooked properly. I think it is more likely that you read about one of the "hemlocks".

Poison hemlock (Conium maculatum) is highly toxic with a large variety of symptoms. This is an introduced species from Europe and is, supposedly, what Socrates drank when sentenced to death for "refusing to recognize the gods recognized by the state" and "of corrupting the youth". Even though it is introduced it has spread over almost all of North America, including most of Canada.

Water hemlock (Cicuta maculata), a native plant of the same family (Family Apiaceae, Carrot Family), is equally as toxic with similar symptoms. This native species has a similar distribution.

You can find more information about these two from the Canadian Poisonous Plants Information System by searching on their botanical names. For Conium maculatum one of the "General symptoms of poisoning" under "Humans" is "death by asphyxiation". For Cicuta maculata, under "General poisoning notes", death is listed as "from asphyxiation". The Indiana Plants Poisonous to Livestock and Pets data base lists these two in their "Extremely Toxic" list. These are definitely two plants to be avoided!

Hydrangea arborescens