The Flowering Winter Annual You Don't Want In Your Yard (& How To Get Rid Of It)

If your grass is a little thin, you may find unwanted hitchhikers in your lawn. Corn speedwell (Veronica arvensis) likes to find gaps in your yard to fill in with its spiky stalks and small blue or purple flowers. Corn speedwell is native to Europe, Asia, and parts of Africa. However, as an invasive species, corn speedwell has spread to parts of the United States, from southern states to the East and West Coast. This winter annual begins growing in the fall, returns during any warm periods through spring, then dies out in the summer heat. Corn speedwell thrives in moist soil, so if the conditions are right and you live in its growing zone — almost everywhere across North America — you are likely to see it in your yard.

While corn speedwell is invasive, not all varieties of speedwell are. One noninvasive variety, spiked speedwell (Veronica spicata) can be perfect for a drought-tolerant garden. However, if you have a more invasive type like corn speedwell taking root alongside your grass, speedwell can be one of the sneaky weeds that wreaks havoc on your yard in the winter. It can crowd out the plants you actually want in your yard! Fortunately, natural methods are highly effective at controlling speedwell, but weed killers can also help as a last resort.

Hand-pulling or weeding corn speedwell can be efficient while the plants are young. You'll want to rip up or mow any speedwell flower heads as soon as they appear to keep them from going to seed and spreading. If you have stubborn, established speedwell patches, you can dig them out with a shovel and reseed with grass. These natural methods can help control corn speedwell immediately, but one of the best ways to get rid of speedwell and other weeds in your yard is to strengthen your preferred grass. To do this, you can try raising the blade on your lawn mower to allow your grass to grow taller and healthier so it can choke out the speedwell on its own. Low nitrogen levels can also contribute to weakened grass and speedwell invasions, so try to increase the available nitrogen in your soil by using a fertilizer, such as Scotts Turf Builder WinterGuard Fall Lawn Fertilizer or Milorganite Recycled Lawn and Garden Nitrogen Fertilizer. 

With these methods, weed killer usually isn't necessary, but speedwell can be controlled with several pre-emergent or post-emergent herbicides. An option like Ortho Weed B-gon will work best when the weeds are actively growing, usually during spring and early summer. Always follow the package directions when using weed killers, and for your protection, wear gloves and rinse them before removing them.  If you have other weeds in your yard in addition to corn speedwell, consider an herbicide product that attacks both. To find out the best approach, take a look at 30 common weeds and how to identify them.