Products that contain aminopyralid (or picloram or clopyralid) should be avoided at all costs!! Their persistence in the environment is a cause for serious concern and could certainly alter your organic gardening processes. And they are not all that better than using something like glyphosate or 2,4-D that will start breaking down immediately after application.

The problem with controlling Canadian thistle is the deep and extensive root system. Burning will not kill it off nor will one-time applications of any herbicide. This will be a frequently repeated process, requiring weekly or biweekly attention until all signs of the weed are gone.

That's interesting...Dow Agrosciences claims Milestone was developed under a "safe herbicide development intitiative" of some sort? So nothing I can do aside from precise repeated hits with glyphosphate? Thanks!

Ok...I am going to stick with the cut/mow and/or roundup program with more frequency. It sounds like glyphosphate is much safer & environmentally friendly. Although I'll be honest, I don't even like using glyphosphate unless absolutely necessary. Thank you!

Just keep in mind, Chris, that the World Health Organization has listed glyphosate containing products as potential carcinogens. Many of the plants that glyphosates are aimed at have developed immunities to the stuff so that poison is not longer as effective as it once was.

If you keep the thistle cut so it has no green leaves to take in sunlight and therefore cannot manufacture nutrients to feed the roots they will eventually die. Spraying poisons to control plants can get to be quite expensive and is not very environmentally safe.

We fought Canadian thistle for years and did not conquer its massive root system until we used a paint brush to painted it with undiluted concentrated round up during blooming season when the roots were weakest. Sorry, you will never beat the aggressiveness of this invasive plant without chemicals. Please, no further lecture needed on chemicals. Sometimes you just need to use them.

Canada thistle, not Canadian thistle.

Thanks for the correction.

Happy to pass it along. ;+)