As I drive down the freeway, I am seeing Poison Hemlock everywhere.
What’s a gardener to do?
As a kid on summer vacation, we used to play “I Spy” in the car. As I have been traveling, you can identify Poison Hemlock going 70 MPH.
Now before you go looking and get in an accident for distracted driving, take a look at the pictures instead.
The questions are:
- What is Poison Hemlock?
- Why is it dangerous?
- What should I do about it now??
Poison Hemlock is a biennial which means it has a 2 year life cycle. It germinates from seed in the spring of the first year. It grows all that 1st summer as a small plant. Then it goes through that first winter and re-emerges as a rosette in March. It grows all spring and bolts this time of year (June), flowers, and sets seed and then dies.
It has distinct pink blotches on the stem:
The problem with Poison Hemlock is the say can cause heart problem, and even heart failure if inhaled.
Joe Boggs, points out in his post below the dangers of Poison Hemlock.:
https://bygl.osu.edu/node/1782
Which leads us to the 3rd question, “What should I do about it?”
Gardeners and professionals may be tempted to spray it with a herbicide or cut it down with a Weed Eater, mower, or brush hog.
The problem with spraying it now, is the plant has already flowered and will set seed before the herbicide can kill the plant.
And that seed will be viable and germinate over the coming several years.
Mowing or weed eating will potentially release the sap into the air as an aerosol which can be inhaled causing potentially serious health risk.
The best thing to do is to note where it is, map it out on paper
and plan on spraying it with a herbicide next spring when it germinates as a first-year plant
or in it’s second year as a rosette.
The most effective control will be achieved in spring when air temperatures are above 40 degrees and after germination, as the plant begins to grow.
Again, Joe Boggs posted an article on the most effective time to achieve the best control:
https://bygl.osu.edu/node/1763
So, as you drive down the highway, have your passengers play “I Spy” and they will see Poison Hemlock in areas along the freeway that have not been mowed.
Happy Summer Vacation!
