Use a two-pronged approach to killing the weeds that invade your lawn, garden and concrete

Iuse a weed killer to kill the weeds that grow in my beds and in cracks in concrete. While it kills the weeds I spray, they always eventually come back. Is there anything more effective or potent I can use that will keep the weeds from coming back? — Tyler

The postemergence weed killers we use to control actively growing weeds generally do a good job of killing them. But if you are dealing with perennial weeds with persistent below ground parts (like bulbs or rhizomes), you need to use a systemic herbicide.

Systemic herbicides are sprayed onto the foliage of the weeds. They are absorbed by the leaves, get into the weed’s circulatory system and move throughout the plant — killing both above ground and below ground parts.

If you use a contact herbicide that just burns down the foliage and