Weeds are a nuisance in every garden and landscape, competing with your plants for sunlight, water and soil. Weeds can be introduced by wind, animals or other carriers, or simply be ornamental landscape plants that have gone wild. Gardeners have several options for controlling weeds, including weed killer herbicides. There are several types of weed killers available, each offering distinct advantages.
Nonselective Post-Emergence Herbicides
Nonselective post-emergence herbicides kill vegetation after it has started growing. Because it's nonselective, these formulations kill all vegetation with which it comes in contact. Example products include Brush Killer and Roundup. Apply the herbicide to spot-treat perennial weeds or in large areas in which you wish to remove all plants. This type of herbicide is typically not used in gardens or near ornamental plants due to its nonselective nature.
Selective Post-Emergence Herbicides
Selective herbicides are used to control and kill specific types of weeds among more desirable vegetation. For example, it is often sprayed on lawns to target broad-leaf weeds within the lawn without killing the ornamental grass. Example products include Vantage and SedgeHammer. When using selective herbicides, ensure both your weeds and your ornamental plants are listed on the label as product formulations vary and not all selective herbicides work alike.
Unlike post-emergence herbicides, pre-emergence formulas are designed to stop weed seeds from sprouting. The herbicide may come as a liquid solution that must be sprayed onto the soil and beneath existing plants, or as a granular substrate material that is mixed in with fertilizer or mulch and applied to the ground. Example stand-alone products include Atrazine and Surflan, while some commercial fertilizers may include a pre-emergence herbicide.
Weeds can be controlled or killed with natural substances for gardeners that do not want to utilize chemicals in their landscape. Example produces include citrus extracts, hot water, fire and vinegar. These products are typically applied on a spot-treatment level rather than on entire landscapes, and are nonselective in their killing effects.