Ohio Noxious Weed Law
Canada Thistle: one of 21 Ohio Noxious Weeds (Source: OARDC).
Mark Loux

The potential for Ohio to become infested with Palmer amaranth has led to some interesting discussions about our noxious weed law in recent meetings where I have been a presenter. With regard to new weed problems such as Palmer amaranth, the gist of the discussion has been how the law can be used to stop the spread of new infestations. This includes how to force landowners to prevent it from going to seed in crop fields or idle land, and how to make sure that the entities responsible for mowing of roadsides do the same. I have to say that after serving in my current position for the last 26 years, I still do not have a good idea of how effective the law is. Many of the plants on the noxious weed list are abundant throughout Ohio. The current list includes:

Russian thistle, Shattercane, Johnsongrass, Wild parsnip, Wild carrot, Oxeye daisy, Wild mustard, Canada thistle, Poison hemlock, Cressleaf groundsel, Musk thistle, Purple loosestrife, Mile-a-minute vine, Giant hogweed, Apple of Peru, Horseweed (marestail), Kochia, Palmer amaranth, Kudzu, Japanese knotweed and Grapevines, when growing in groups of one hundred or more and not pruned, sprayed, cultivated or otherwise maintained for two consecutive years.

Weeds have been designated as noxious here in Ohio for various reasons including toxicity to humans or animals (poison hemlock, cressleaf groundsel), invasiveness (kudzu), negative impact on natural areas (mile a minute vine, purple loosestrife), and potential to cause economic loss (palmer amaranth, apple of Peru). Some were added because they have been extremely problematic in other areas of the country, and the goal is to prevent establishment here (Russian thistle, musk thistle). Canada thistle was added so that federal agencies could allow early-summer mowing of CREP and similar areas in order to prevent seed production. I don’t know what the deal with the grapevines is but someone had a good reason I guess.

There are several components to the law that accomplish the following: 1) mandates that township trustees and others responsible for roadside vegetation control will use mowing or other methods often enough to control noxious weeds; and 2) provides township trustees the authority to control noxious weeds after a landowner or other controlling interest (including Department of Natural Resources and the state) has been notified and will not, and bill the landowner for the cost of control. Specific questions about the noxious weed law should be directed to the Ohio Department of Agriculture. Details of the law can be found by doing a web search on “Ohio noxious weed law”.

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