Answer: Perennial weeds, those with extensive root systems, are really difficult to eradicate. The best approach is to dig them out, roots and all. If that is not practical, you may be able to suffocate them by cutting them down to ground level then covering the soil with several thicknesses of newspaper and topping that off with a weed block fabric. There are some powerful herbicides you can use, but they are non-selective, meaning they will kill all vegetation they touch. If you decide to use vegetation killers, be very careful around your desireable plants and be sure to apply according to label direction.
Best wishes with your weed eradication project.
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