Some herbicides are designed to control a broad range of weeds, while others are designed to control only selected types of weeds. Post emergent herbicides can be selective or non-selective. Products such as Roundup can be considered total vegetation, non selective and post emergent. A non-selective herbicide tries to kill most plants while a selective herbicide is designed to kill specific types of plants, usually grasses or broad leaf weeds. elective herbicides are a type of herbicide that will only kill a certain type of plant while leaving other plants unaffected.