Common Virginia Weeds

Annual Bluegrass (Poa annua)

Annual bluegrass is a light green, low growing bunch type grass. It’s easy to pick out in most lawns due to its light color. Annual bluegrass does well in lawns that are cut short. It also likes areas with low pH, compaction, poor drainage and/or shade. When turf is fertilized at improper times and given frequent light watering, tends to favor annual bluegrass. In irrigated lawns, annual bluegrass seeds can germinate and persist through the fall growing season.

Corn Speedwell (Veronica arvensis)

Corn speedwell is a small, low-growing annual that often goes unnoticed. Speedwell can be a common weed problem in newly established areas of cool-season turfgrass. Upper and lower leaves of corn speedwell differ in appearance and arrangement. Lower leaves are rounded, toothed and arranged opposite. Upper leaves are smaller, pointed and arranged alternate.

Control: Control is often difficult due to speedwell’s inconspicuous nature. Typically, by the time it’s noticed it has already flowered and set seed. Speedwell is often found in dry areas with low soil fertility. Improving the turf with overseeding, proper fertilization and proper irrigation can help prevent speedwell.

Bittercress (Cardamine hirsuta.)

Bittercress has deeply loped leaves that are larger at the base of the plant than the top. Small white flowers are held in clusters at the top of branches. Bittercress seeds germinate in 5 days and can produce seedling in 5 weeks after germination.

Control: Manage fertility to favor turf by fertilizing based on soil testing and adjusting how much nitrogen is applied. Improve surface drainage and where appropriate, selective pruning to reduce shade. Overseed thin areas as needed to limit the ability of these weeds to establish or returning to the lawn.

Common Chickweed (Stellaria media) and Mouse Ear Chickweed (Cerastium vulgatum)

Chickweed and mouse ear chickweed are among the most common cool season weeds. Common chickweed is an annual, while mouse ear chickweed is either an annual or perennial. Chickweed prefers heavy, wet/poorly drained soil and thrives well in the shade.

Control: Steps may need to be taken such as improving drainage, aeration and a top dress with compost, mow high and overseed to thicken the lawn. These steps can all help make conditions more favorable for turf than chickweed. Where practical, selective pruning of nearby trees and shrubs to increase light will also help grass compete with chickweed.

Ground Ivy aka Creeping Charlie (Glechoma hederacea) and Wild Violet (Viola sp)

Ground ivy and wild violet are stubborn weeds with similar appearance. Ground ivy is a sprawling weed that grows well in moist soils under shade and in full sun. It also likes wet/poorly drained soils. Violets prefer shady conditions where they have the competitive edge over turf.

Control: When possible, increase available light through selective pruning of nearby trees and shrubs to favor grass over these weeds. Increase mowing height and overseed areas of thin turf to suppress weeds. Improving drainage will make conditions less favorable for ground ivy. These weeds are resistant to many broadleaf herbicides which takes several precise applications by a trained professional to control. They are best treated in the spring, and often need repeated applications for full control.

Henbit (Lamium amplexicaule) and Deadnettle (Lamium purpureum)

Henbit and deadnettle are winter annuals that look alike. Both have square shaped stems and flower in the spring. These weeds prefer high fertility soils.

Wild Onion (Allium ascalonicum) and Wild Garlic (Allium ursinum)

These close cousins are common turf weeds. They have very similar appearance and controls are the same for both. Wild garlic is more persistent because it produces bulblets which are often left in the soil when the plant is hand pulled. Both do well in thin lawns and in poorly drained soil.

Control: Improve drainage, aerate and top dress with compost, mow high and overseed to thicken the lawn. Manage fertility to favor turf by fertilizing based on soil testing and adjusting how much nitrogen is applied. Increase mowing height and overseed thin areas to limit the ability of these weeds to establish in the lawn. Hand pulling clumps isn’t very effective. Leaves snap off easily and regrow. Mowing just prior to herbicide application will improve effectiveness, but still may not provide optimal control.

Clover (Trifolium repens), Wood Sorrel (Oxalis sp) and Black Medic (Medicago lupulina)

There are several clovers that can be found in lawns. White clover is the most common and most persistent. Clovers are easily identified by their trefoil leaves and clustered flowers. Being legumes, clovers will add nitrogen to the soil.

Black Medic

Clover and wood sorrel are indicative of low fertility soils. Amending soils to an appropriate pH and providing adequate fertilization will aid in making grass more competitive than clover and wood sorrel. Mowing high can help with lower growing clovers and wood sorrel. Wood sorrels and annual clovers are best treated chemically in the spring. White clover, however, is best treated in the fall. Both can be a challenge to control. Clovers are susceptible to many herbicides but if the stand is well established, multiple applications may be necessary.

Dandelions (Taraxacum sp) and Thistles (Cirsium sp)

Both have rosette growing patterns and often have milky sap. Thistles tend to be larger and have waxier leaves, which makes them harder to control chemically. Dandelions are hard to control because of their prolific seed production and the ease at which their seeds disperse in the wind.

Control: Dandelion, bull thistle and Canadian thistle are most effectively treated in the fall. Musk thistle and plume less thistle are easier to kill and are most effectively treated in the spring. Bull and Canadian thistles are more resistant to chemical control.

Crabgrass is annual grass that usually makes its first appearance in spring as soil temperatures in the root zone reach the mid-50s. It prefers open areas, and can often be suppressed by tall, thick stands of turf.

Goose grass sends stems out of a central point in regular pattern, like spokes of a wheel. While it has outreaching stems, goosegrass does not root at the node. Goosegrass will germinate throughout the summer if conditions are favorable just like crabgrass but requires warmer soil temperatures, so it starts to a appear a few weeks after crabgrass in the spring.

Control: Thick turf, mowed high (3.5-4 inches) will shade out most crabgrass and goosegrass before they get started. Pre-emergent herbicides are not 100% effective and may need to be reapplied over the season depending on the formulation.