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Turf Tips: Controlling Winter Weeds

This post was originally published in March 2017 and was updated with new product recommendations on April 2, 2021.

David Yost, Merrifield Plant Specialist and Turf Expert

Spring is just around the corner. Before long you’ll be sowing grass seed, applying fertilizer, and mowing the lawn! To return your lawn to a thick, healthy state, March is the time to begin controlling pesky winter weeds currently taking over your lawn, and preventing summer weeds.

Winter weeds include chickweed, bittercress, henbit and deadnettle, as well as perennial weeds, such as clover, dandelion and wild violets. These winter weeds actually germinate in late September and early October, but they often go unnoticed in the fall when they’re just young seedlings. They overwinter as a small rosette, and come spring they are ready to strike with a vengeance!

Winter weeds typically flower in March, but can start blooming in February if temperatures are warm! Regardless of when they bloom, you can stop them dead in their tracks with the right control product.

Products to Control Winter Weeds

Two of our recommended products for Trimec Speed (a new product from Gordon’s for residential use, comparable to Speed Zone, their commercial product), and Bonide Weed Beater Ultra. Generally speaking, liquid weed killers are ideal for controlling actively growing weeds because they typically provide better surface area coverage than granular products. Plus, since they are applied as a spray, they can be turned on or off as needed, limiting waste or overuse.

We really like Speed Zone as it contains the same three active ingredients as the other products, but also has Carfentrazone, which makes it work faster and be effective at lower temperatures. Speed Zone also has a two-week waiting period before reseeding the lawn, compared to the three-week waiting period that most of the other products require. This allows you to get started on your overseeding project sooner so that you will be growing thick and healthy turf.

Most winter annuals can be controlled with just one application of weed killer. However, because perennial weeds live year-to-year with an established root system, some of them may be more difficult to control than others. Clover, for example, can typically be controlled with just one application, while others, such as wild violet, may take several applications to effectively control.

Regardless of the weed control product you use, none of them will hurt your lawn if they’re used as directed. Be sure to treat any existing broadleaf weeds in the lawn now, so that you’ll be ready to start building a beautiful new lawn from a clean slate.

Turf Tips: Preventing Summer Weeds

David Yost, Merrifield Plant Specialist and Turf Expert

Untreated summer weeds have a way of wreaking havoc on our lawns. The good news is that they haven’t germinated yet. You can intervene in the process by applying a summer annual weed preventer now. If you haven’t already, you’ll want to start by treating any winter weeds that currently reside in your lawn.

Types of Summer Weeds

Summer weeds include varieties of grassy and broadleaf weeds. Grassy weeds include crabgrass—the most infamous of all—goosegrass, foxtail and Japanese Stiltgrass. Japanese stiltgrass is now the most common weed in the state of Virginia. Each of these plants produces over 1,000 seeds that will remain viable in the soil for 3 to 5 years.

Many broadleaf weeds begin germinating in early spring and include spotted spurge and lespedeza, among others. Regardless of what type you have, all of these will stick out like a sore thumb in an otherwise healthy and attractive lawn.

Preventing Summer Weeds

To determine which product you should use to prevent summer weeds from attacking your lawn, you must first decide if you are going to seed the lawn this spring.

If you’re not planning to seed the lawn

If you are not seeding the lawn this spring, there are three different products you can use to control summer weeds:

  • Preen Crabgrass Control
  • Organic Corn Gluten

Preen Crabgrass Control contains dimension, a very effective ingredient that prevents summer weeds. Both products will remain active in the soil for 2 to 3 months, which means you need to put down two applications per year (for example, one in mid-March and another in early June).

Corn gluten is an organic weed preventer, which naturally inhibits all seed growth. This product will last about 1 to 2 months in the soil, which means you need to put down two applications per year (for example, one in mid-March and another in late April or early May).

If you put down two applications of any of these products in the spring and early summer, your lawn will be ready for fall seeding. Fall is an ideal time to seed as the warm days and cool nights provide the optimal growing conditions for cool season grasses.

If you are planning to seed the lawn

If you are seeding the lawn this spring, we recommend using Scott’s Step 1 for Seeding (Starter Food with Weed Preventer). This product contains tenacity, an ingredient that can distinguish between the “bad” summer weed seeds and the “good” grass seeds. This product also provides starter fertilizer to help your grass seed germinate.

Once your new grass seed has germinated and been mowed twice (this typically occurs about 6 to 8 weeks after seeding), you can apply a second application of another summer annual weed preventer. For the second application, we recommend using one of the three products for not seeding your lawn. By this point, your new grass will be mature enough to withstand the dimension ingredient. You should only use the Scott’s Step 1 for Seeding for the primary application as your lawn doesn’t need a second application of the starter fertilizer that comes automatically in the product.