Answer: Don't give up! Canada thistle is a creeping perennial that reproduces from vegetative buds in its root system and from seed. It is difficult to control because its extensive root system allows it to recover from control attempts. Persistence is imperative so the weed is continually stressed, forcing it to exhaust root nutrient stores and eventually die. Re-treatment for one to three or more years after the initial application is common. Just keep working at it and eventually you will gain control. Your local cooperative extension office may have a list of acceptable chemical controls so check with them. Perhaps something new to your county is available. Hope so!
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