Is there a product that will kill weeds in the garden without killing the plants you want to keep?
There are herbicides that kill everything, ones that only kill grass and ones that kill plants with broad leaves (not like grass). But I don't think there is an herbicide that can tell good plant from weed. Most weeds can be manually removed but some are so persistent that herbicide makes sense. In those cases, I have used a 1/4 or 1/2" foam paintbrush to apply herbicide directly to the weed. I have also made a cone with glossy paper and used that to protect surrounding plants and direct the spray to the weed. The point of GMO corn, etc is to allow farmers to spray weeds without killing the corn. We aren't there with garden plants!