Control Canada thistle in lawns/greenways - Ask Extension
I am in an HOA with many acres of greenway. In some areas we have a lot of Canada thistle growing which is very hard on feet in sandals, etc.
We h...
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Control Canada thistle in lawns/greenways #867225
Asked May 06, 2024, 12:11 PM EDT
I am in an HOA with many acres of greenway. In some areas we have a lot of Canada thistle growing which is very hard on feet in sandals, etc.
We have tried researching which herbicide can be used to control it, but it seems most everything listed to control it is intended for agricultural or restoration use.
And we don't know what is allowed for use on turf grass in residential greenways.
Our landscaping company uses SpeedZone to control other broadleaf plants (dandelions etc.) but it has little effect on the thistle.
Milestone was suggested, but it's label says it can be used on ", permanent pasture, industrial areas (including but not limited to rights-of-way and military bases) and other non-crop areas." Does that mean we cannot use it on greenways?
If not do you have any suggestions of what we can use?
Washington County Oregon
Expert Response
Cindy: Milestone and a chemically related product both have incredibly long lives. They are also active in very small quantities. Problems started when grass clippings were removed and sent to composting facilities and since the active ingredient remained with all its herbicide activity, the compost was toxic to many vegetable and other plants.
Livestock that graze grass and/or grass hay with Milestone residues will have poop laced with Milestone in plant active quantities. Again, has been a problem with use in gardens and landscapes.
It can get into the root systems of some woody trees and shrubs.
So these herbicides can't be used on lawns. Not sure how your greenway would be judged but it is better to err on safety.
There are some products that can help but you need to work with your applicator and the applicator with their supplier to get the best fit for your situation. Chip Bubl. OSU Extension/Columbia County (recently retired)
Livestock that graze grass and/or grass hay with Milestone residues will have poop laced with Milestone in plant active quantities. Again, has been a problem with use in gardens and landscapes.
It can get into the root systems of some woody trees and shrubs.
So these herbicides can't be used on lawns. Not sure how your greenway would be judged but it is better to err on safety.
There are some products that can help but you need to work with your applicator and the applicator with their supplier to get the best fit for your situation. Chip Bubl. OSU Extension/Columbia County (recently retired)
