Speedwell in the lawn
This thinly grassed lawn is allowing speedwell, a winter-annual weed, to creep in.
George Weigel

You’re not imagining if it seems like your lawn has a lot more weeds now than going into winter. That’s because there’s a family of weeds that actually sprout best in autumn’s cooling temperatures – and even during mild spells in winter. These are so-called “winter annual” weeds that sprout when most other plants are dormant, then take off like a shot at the first inkling of late-winter warmth.

Winter annuals grow both in lawns and garden beds. They usually die back later in spring after flowering and depositing new seeds for next year’s invasion. Common examples are speedwell (a creeping blue-bloomer), chickweed (a creeping white-bloomer), hairy bittercress (a wiry-stemmed plant with tiny white flowers), and henbit and deadnettle (mint-family plants with purple flowers). A few perennial weeds (ones that come back year after year) also can germinate in fall and mild winters, including two of the most common lawn weeds – dandelions and plantain.

What to do

The first line of defense against these earliest of weeds is to never let any of them go to seed. Remember, every weed you get rid of before going to seed could be preventing hundreds later.

If you wait until later in spring to act on winter annuals, you’ll only be trying to control plants that would die anyway after they’ve set the stage for next year. Smaller patches of winter annual weeds and perennial weeds can be removed by hand. For larger spreads, or those tough to pull by hand, treat with liquid herbicide. Be sure to check the label to be sure the product controls your specific weed trouble.

For bigger outbreaks, the whole lawn can be treated with a granular weed control labeled for use in lawns, such as GreenView Broadleaf Weed Control plus Lawn Food with GreenSmart. If you commonly suffer from crabgrass as well, use GreenView Fairway Formula Spring Fertilizer Weed and Feed and Crabgrass Preventer as your all in one lawn weed control.

Hairy buittercress in lawn

Hairy bittercress is beginning to flower in this lawn. George Weigel

A thicker lawn, is best weed defense long-term

The fact that your lawn is dotted (or worse) with weeds is a sign that the grass isn’t thick enough. The best long-term defense against any weed is a lawn that’s so thick that nothing has a chance to elbow its way in. In most regions of the U.S., early spring and early fall are the two best times of year to overseed thin lawns with additional grass seed or to patch bare spots.

In areas where you’ve killed weeds with herbicides, read the product labels for instructions on how long to wait before planting grass seed. Most products require at least a three-week interval between application and grass-seeding.