Q. How can I safely get rid of 13 years of mint that is now overtaking my entire herb garden?
A. It is quite difficult to eradicate an aggressive perennial herb like mint because of its elaborate and tenacious system of underground runners. Your best solution at this point is to wait until the mint is actively growing in late spring or early summer before spraying the entire patch with an herbicide containing glyphosate. Dig up your prized herbs first and move them to another part of the garden before you apply this herbicide, since it is nonselective and will kill all plant material it contacts. Glyphosate has a very short residual life span in the soil, so you will be able to replant this area quickly with herbs or any other plants you choose. As with all herbicides, read and follow package directions carefully.