Hairy bittercress (Submitted photo / Bill Snyder, OSU Extension)

This late in the season, many of us are growing as tired as many of our plants. But it is a very important time to think about what weeds will wreak havoc on your garden and landscape next spring.

Take notice of the tiny green seedlings popping up in the landscape. These little seedlings are quite apparent in flower beds, around sidewalks and around landscaped shrubs and trees.

If you are looking closely, you’ll see the seedlings, ever meek and mild this time of year. They emerged in late August and will continue to gain strength through the late fall. When spring arrives, they will grow with explosive speed, bloom, then produce seed before you can blink.

There is never time to get rid of them in the spring!

These weeds are called winter annuals. That is because they germinate now, stay green all winter and are done by early spring. Unlike summer annual weed species in the spring, winter annual weed species grow more actively at temperatures near freezing.

To control these weeds now, mulch is your best friend.

Before mulching, use a hoe or string trimmer to remove the seedlings. Apply a fresh coat of mulch 2 to 3 inches thick on the area to block out the sunlight. This prevents other weed seeds from germinating.

In addition to weed control, the mulch will help moderate soil temperatures, aiding your plants through the freezes and thaws of early fall. This will allow roots to get a good foot hold before the colder temperatures of winter arrive.

In general, these weeds will be located where you had issues in early spring, as just a couple of weeds produce a ton of seed. If you know you had blooming weeds in an area in March, there may be a carpet of seedlings in that area right now, especially if you did not add a 2-to-3-inch layer of mulch this year.

The three most abundant winter annuals we see in our Plant and Pest Clinic each year include:

• Hairy Bittercress — This plant’s looks will soon look like a small, rounded rosette of scalloped leaves. It emerges as two round cotyledons, then gains two scalloped, true leaves quickly. It is a lime-green color. It is a member of the mustard family. In spring, it will send up a central flower head with white flowers.

• Purple deadnettle — The seedling looks similar to hairy bittercress at first, but is softer to the touch and has more of a spade shaped leaf. In spring, the upper leaves expand, turning a purple color with tiny pink / purple flowers.

• Chickweed — These seedlings have more elongated, pointed leaves. It is a bright lime green color.

For photos to identify your winter annuals, go to https://bygl.osu.edu/node/1909.

For even more weed management tips and photos of other weeds, go to http://go.osu.edu/winterannuals.

Barrett is the Ohio State University Extension educator for agriculture and natural resources in Mahoning County.