Warming temperatures and spring rains signal not only the annual resurgence in the growth of Virginia's lawn grasses but also the arrival of a host of weeds. Mike Goatley, turf specialist for Virginia Cooperative Extension, has tips for homeowners trying to rid their property of spring weeds and restore a healthy, thick lawn while protecting the environment.

“The primary reason a plant is considered to be a lawn weed is because it somehow distinguishes itself from the lawn grasses,” said Goatley in his recent Turf and Garden Tips podcast on Spring Postemergent Lawn Weed Control. “While bright, multi-colored plants in the landscape beds are very often desirable, most people value uniformity as a key characteristic of what defines a great-looking lawn. Weeds disrupt this uniformity because of differences in shape, size, and color.”

Although most weeds are simply eyesores, some are invasive, potentially injurious, or poisonous and warrant control measures. Whether or not a weed qualifies as a serious pest, the first step in understanding control alternatives is to identify it. This can prevent unnecessary application of herbicides for many winter annual weeds, for instance, in the last stages of their life cycle and will soon die as temperatures warm.

“The key to success is knowing the weed and its life cycle to make an appropriate herbicide choice and application,” Goatley said.

Local Extension offices can aid in weed identification and control alternatives. In addition, Extension turfgrass weed specialist Shawn Askew has a turf weeds website that features photos and descriptions of the region’s most prevalent turf weeds in all stages of growth and development.

After identifying a weed, the next step is to investigate why it is present. Because weeds exploit low-quality turf, the best weed control is a thick, healthy lawn. When this does not happen, a homeowner needs to uncover what factors are impeding the turf’s performance.

“Are there soil-related problems such as pH, fertility, poor drainage, or compaction?” Goatley asked. “Could the limiting factor be shade? Was the turf previously damaged by an environmental extreme or pest attack?”

A homeowner who makes smart decisions with lawn fertility, mowing, and irrigation is fighting weeds by creating lawn conditions that optimize turf growth and development. In some cases, herbicides can be applied before weeds emerge to control germinating seeds, but when this does not take place or does not prevent weeds, a postemergent herbicide is needed.

Goatley urges homeowners to choose wisely when selecting herbicides and to follow the directions on the label. Pre- and postemergent herbicides must be carefully distinguished because the former do not control existing weeds and the latter do not fight germinating weeds.

“And the importance of carefully following the label cannot be overstated in terms of product performance and safety to you, the turf, and the environment,” Goatley said. He added that important considerations when selecting an herbicide and reading a label include possible restrictions on types of grasses, air temperature during application, and irrigation.

The Turf and Garden Tips website has more research-based information about Extension gardens, lawns, and ornamentals. In addition, a previous article has tips on summer lawn care.

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