Thistle Control - Ask Extension
I am looking for suggestions to eradicate a large stand of CANADIAN THISTLE that is growing thru BLUE RUG JUNIPER groundcover that would like to rema...
Knowledgebase
Thistle Control #872903
Asked June 13, 2024, 8:19 AM EDT
I am looking for suggestions to eradicate a large stand of CANADIAN THISTLE that is growing thru BLUE RUG JUNIPER groundcover that would like to remain in place
Howard County Maryland
Expert Response
Thank you for your question and I'm sorry to hear you're battling canada thistle. It will be especially difficult to combat growing within the confines of your prostrate juniper, but still doable.
The first step would be to yank/pull (if possible) all that you can. If you cannot pull (which is likely because its roots are likely intertwined with those of the juniper), then cut the stem as low as you can. Continuing to do this will prevent the plants from maturing and going to seed. The seeds tend to germinate the first year but can remain viable in the soil for up to 20 years, so preventing seed heads from developing is a top priority.
Herbicides tend to provide mixed results with thistle, but if you purchased a strong concentrate you could use a small paint brush to paint the freshly cut stems. Since Canada thistle tends to spread by both seed and rhizome, the root system is also your enemy, hence the recommendation for applying herbicide. When doing so with a paintbrush you're sending the herbicide into the vascular system of the plant while simultaneously preventing damage to your juniper. Yes, it is tedious, but battling thistle is a marathon, not a sprint. You will have to be vigilant and may need to repeat this process several times this year, and possibly in additional years.
If you have further questions, feel free to ask them. And if you want another opinion, advisory assistance with how to control this noxious weed in MD is available through your local county noxious weed control program, or through the Maryland Department of Agriculture at<personal data hidden>.
Good luck!
The first step would be to yank/pull (if possible) all that you can. If you cannot pull (which is likely because its roots are likely intertwined with those of the juniper), then cut the stem as low as you can. Continuing to do this will prevent the plants from maturing and going to seed. The seeds tend to germinate the first year but can remain viable in the soil for up to 20 years, so preventing seed heads from developing is a top priority.
Herbicides tend to provide mixed results with thistle, but if you purchased a strong concentrate you could use a small paint brush to paint the freshly cut stems. Since Canada thistle tends to spread by both seed and rhizome, the root system is also your enemy, hence the recommendation for applying herbicide. When doing so with a paintbrush you're sending the herbicide into the vascular system of the plant while simultaneously preventing damage to your juniper. Yes, it is tedious, but battling thistle is a marathon, not a sprint. You will have to be vigilant and may need to repeat this process several times this year, and possibly in additional years.
If you have further questions, feel free to ask them. And if you want another opinion, advisory assistance with how to control this noxious weed in MD is available through your local county noxious weed control program, or through the Maryland Department of Agriculture at<personal data hidden>.
Good luck!
