University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Managing Weeds in the Landscape & Gardens

April 29, 1999

Plenty of rainfall and warming temperatures have given landscape plants the signal to get growing again. As you’ve probably noticed, weeds have been developing as well. Examine your options for control now, before the situation gets out of hand and the weeds prevail.

One route commonly taken, not necessarily the best, is applying herbicides (weed killers) for weed control. Although there are many herbicides on the market, but be sure the product is labeled for your intended use. A product used on a lawn may not be labeled for vegetable crops, even though it may control the same weed in both areas. Also, a herbicide may damage some types of ornamental or food crops and not others.

Preemergence herbicides are applied to the soil to kill weed seeds as they germinate. Trifluralin (Preen, Treflan) is an example of a product available for gardens and landscape beds; make sure all types of plants in the area being treated are on the label. There are several preemergence herbicides available for use on lawns to prevent crabgrass, most of which are combined with lawn fertilizer.

Postemergence herbicides are applied directly to existing weeds. Once again, read product labels very carefully. Glyphosate (Roundup, Kleenup, Kleeraway) is an example of a nonselective postemergence herbicide, meaning it can harm or kill any green vegetation it is applied to. Selective postemergence herbicides include those applied to control broadleaf weeds growing in a lawn or a few that can be used to control grasses growing in broadleaf plants.

Want to avoid herbicides or unsure about using them? Probably the most effective way to get rid of weeds is to pull them out by hand, roots and all. Depending on how many exist and how big the area is, this may or may not be realistic. Frequent cultivation of garden soils can also be effective; cultivate as shallow as possible to avoid bringing up more weeds and to prevent damaging root systems of plants. Persistence is required to stay ahead of the weeds.

Finally, mulching is an excellent way to prevent weeds and conserve soil moisture. Organic materials (straw, compost, shredded bark) add organic matter to the soil as they decompose. Synthetic materials include black plastic (polyethylene film) for vegetables and commercially available fabric mulches (usually covered with bark or stone) for ornamental plants.


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