As the weather cools and the year draws to a close, warm-season Texas lawn grasses start to go dormant. While the lawn is dormant overwinter, it is more vulnerable to weed growth. Since the grass is not actively growing, it cannot choke out winter weeds and the weeds that do grow will be more visible. Removing winter weeds will make the lawn more attractive now, and limits competition with the turfgrass in the spring.
Types of Winter Weeds
There are two main types of winter weeds. Perennial weeds live for more than one growing season. These include weeds such as dandelions, dallisgrass, wild garlic, and wild onion. Annual weeds live for only one growing season, and germinate each year from new seeds. Perennial weeds are often eliminated before winter by weed controls used during the spring and summer. It is the winter annual weeds that are most likely to appear in lawns after the grass has gone dormant. These include varieties of chickweed, annual bluegrass, speedwell, and bittercress.
Herbicide Controls
Annual weeds are usually prevented by using a pre-emergent herbicide that stops the weeds seeds from germinating. They often come in granular form to spread evenly across the lawn. For winter annuals in Texas, per-emergents are applied in late September and early October, or before temperatures at night consistently drop below 60 degrees Fahrenheit. If that window has passed, there are still ways to effectively kill and prevent weeds in the lawn.
Products that combine pre-emergent herbicides with a chemical that kills existing lawn weeds are a good choice for late fall application. Before choosing an herbicide, make sure you know what type of grass is growing in your yard so you can select a herbicide that will not harm the lawn.
A product such as Bayer’s Season Long Weed Control For Lawns kills weeds that are already growing, prevents new weeds for about 6 months, and will not harm most lawn grass. It should not be used on carpet grass, desirable clovers, or certain varieties of St. Augustinegrass such as Floratam.
Natural Weed Controls
Most natural weed controls involve hand pulling and prevention of weeds. The best prevention against weed growth is a thick, healthy lawn. Thatching and aerating the lawn once a year, keeping up a healthy fertilization schedule, and mowing regularly will drastically reduce the number of weeds during the spring and summer growing seasons. In the winter, however, warm-season grasses go dormant and cannot compete with winter annuals.
Hand-pulling can work well for small lawns or small numbers of weeds. When there are few weeds present, this can be the most practical form of weed removal, particularly for annual winter weeds. Some homeowners also apply corn gluten meal as a pre-emergent, with mixed results.
While your lawn is dormant over the winter, there are a few steps you can take to prevent the growth of weeds. Applying an herbicide for season long weed control or pulling weeds by hand will help keep the lawn free of unattractive weeds.
