From Across the Field – 6/11/2020

Beware of Poison Hemlock

Last week I finished up with a paragraph on Poison Hemlock, a noxious, invasive weed that is starting to be more prevalent across the county. Perhaps it is coincidence, but the majority of questions this past week have been about Poison Hemlock, the challenge it presents, and control. So let’s review:

Poison Hemlock is a noxious weed that is extremely toxic to livestock. It looks like wild carrot or “Queen Ann’s Lace”, however it can grow to be 6 to 10 feet tall. Poison Hemlock is toxic to both people and livestock, often leaving serious blisters on those who come in contact with the plant. Ingestion of the any part of the plant can be fatal.

If found in a ditch bank or field, poison hemlock can be partially managed by mowing and tilling. The most effective control approach involves properly timed applications of post-emergent herbicides including glyphosate (e.g. Roundup) or 2,4-D.  However, applications of herbicides must be made before the plant bolts from the rosette stage to have any chance of reducing seed production this year.

At this point in the growing season mowing the plants is good option, followed by a fall application of herbicide. Mowing in the next week will help reduce seed production. Poison Hemlock is a biennial weed, that if controlled during the rosette stage in the fall, can be managed relatively well compared to some of our other noxious weeds in Ohio.

In other agriculture and natural resources news the 9th Circuit Court of Appeals decision which ordered the U.S. Environmental Protection Agency to vacate the registration of three of the four dicamba products that had previously been approved for use on dicamba tolerant soybeans. Those products are: XtendiMax with VaporGrip Technology, Engenia Herbicide, DuPont FeXapan with VaporGrip Technology.

As of the writing of this column, Distribution or sale by any person is generally prohibited except for ensuring proper disposal or return to the registrant. Growers and commercial applicators may use existing stocks that were in their possession on June 3, 2020, the effective date of the Court decision. Such use must be consistent with the product’s previously-approved label, and may not continue after July 31, 2020. Stay up to date on issue by checking Ohio Department of Agriculture’s website or at, where our weekly agronomy newsletter can be found.

Looks like some rain in the forecast today which will be of benefit to farmers and gardeners across Henry County. We have had a nice stretch of field work over past couple of weeks, where hay has been baled, herbicide applications completed, and side dressing of corn with both manure and commercial fertilizer has taken place.

I know after the past three springs my dad and brother were glad to be able to make some nice first cutting mixed hay. After today’s rain they will be busy finishing up that first cutting, baling rye straw, and in a couple of weeks the ram battery will return to pasture for the 2020 breeding season. Always a busy time in agriculture when the sun is shining in June. Ill end this week with a quote from Albert Einstein: “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.”. Have a great week.





Garth Ruff,

Agriculture and Natural Resources Extension Educator

OSU Henry County Extension

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