Pre-emergence can help control weeds


Jeff Floyd


Controlling weeds while they are small is easier and less expensive than trying to get rid of them once they have matured. One of the best ways to control them is to properly fertilize and water the yard to give lawn grass a competitive edge. In flower beds, maintaining a 3- or 4-inch layer of woodchip mulch is an attractive way to suppress weeds. However, in flower beds and lawns, pre-emergent herbicides should be your first choice to prevent weeds.

Fall and spring temperatures are ideal for weed seed development. Therefore, February and September are excellent times to apply these preventative herbicides in anticipation of weed development. The active ingredients of pre-emergents disrupt the growth of very young cells but have little effect on less vigorous cells.

Weed seedlings depend on actively dividing cells in their roots and shoots to establish themselves. Pre-emergents often stop cell division and effectively short-circuit the growth of young weeds. In this sense, they are selective and only harm tender young plants. Even their improper use will not destroy your lawn. Pre-emergences have little or no effect on mature plants because established trees, shrubs and grasses are not entirely dependent on rapidly dividing cells to stay alive.

On the other hand, using a post-emergence is more likely to result in accidental damage to desirable landscape plants. Damage caused by many post-emergent herbicides is not limited to seedlings. For example, glyphosate, which is the active ingredient in Roundup, kills plants by stopping the production of an essential protein that virtually all plants need. Misuse of glyphosate can lead to massive destruction of any plant it comes in contact with.

Labor Day and Valentine’s Day are easy dates to remember and great dates to apply pre-emergencies. Granular pre-emergents are readily available at home improvement stores and garden centers. This formulation is easy to use as it can be applied with a common fertilizer spreader.

If you decide to go out this Labor Day and apply a granular pre-emergence, as with all herbicides, read and follow label directions. It’s the law.


About Author

Comments are closed.