Annual Bluegrass (Poa annua)
Description: This bright green grass grows in clumps and bears grain-like seedheads, usually in spring. When Annual Bluegrass goes to seed, the light-colored seedheads give a lawn a speckled look. Plants die out as summer heat builds. Seeds germinate in late summer.
Conditions that favor its growth: Overwatering, compacted soil, scalped turf
Treatment options: Water lawn properly,and aerate. Mow lawn at the proper height. Time mowings so that Annual Bluegrass never has a chance to set seed. Use a pre-emergent herbicide in late summer before Bluegrass seeds germinate.
Description: Blue-green grassy leaves sometimes have a purple tinge. Leaves form a tight, crab-like circle. Plants grow in bare or weak areas of existing lawn. Seedheads appear in summer and fall and stretch upward, standing above foliage.
Conditions that favor its growth: Overwatering or underwatering, mowing the lawn too short
Treatment options: Water lawn properly, and mow at the correct height. The best defense against Crabgrass is growing a healthy lawn. To prevent Crabgrass, apply a pre-emergent herbicide in early spring. Application timing is important. Check with your local Cooperative Extension System office for details on the right time for your region. If you already have a few plants, you can hand-pull them. Or try 5 In 1 Weed & Feed. It kills listed lawn weeds PLUS kills Crabgrass, all in one step.
Description: A rosette of bright green leaves hug soil. Seed stalks appear in summer, standing above leaves.
Conditions that favor its growth: Overwatering, compacted soil, shade; plants also appear in sunny areas of poorly maintained lawns
Treatment options: Water lawn properly, and aerate. Pull plants when young and soil is moist, like after irrigation or rain. Mow frequently in summer when seed stalks start appearing to prevent seed maturation. Applying a post-emergent herbicide will kill established plants. Learn why a fall herbicide application works best.
Creeping Charlie (ground ivy)
Description: Dark green, round leaves have scalloped edges. Aggressive plants trail; stems root as they grow. Purple flowers appear in spring.
Conditions that favor its growth: Shade, moisture, poor soil fertility; plants occur most frequently in shade, but do grow in sun, too
Treatment options: Prune trees, if possible, to increase sunlight to lawn area. Water and fertilize the lawn properly. Hand-pull or dig small patches of Creeping Charlie. Spot-treat using a broadleaf herbicide. Timing is critical when treating this weed; follow label instructions carefully. Plant and establish shade tolerant grass after treatment to prevent a return of this or other weeds.
Description: A basal rosette of green, toothed leaves is topped with yellow flowers. This is a perennial weed that grows from a taproot, which can be 2 to 3 feet long. Puffballs spread seed easily.
Conditions that favor its growth: Thin lawn, nearby sources of infestation
Treatment options: Grow a thick, healthy lawn. Mow at a higher height to allow grass to shade soil and keep blown-in seeds from germinating. Dig or spot-spray individual plants. It also helps to apply a pre-emergent herbicide to your lawn to deal with seeds that might be blowing into your yard. Apply a post-emergent herbicide to kill established Dandelion plants. Learn why a fall herbicide application works best.
Description: Classic three-leaf Clover with three bright-green leaves attached to one stem. Leaves have crescent-moon white marks. Small white flowers appear above leaves from spring to fall.
Conditions that favor growth: Poor soil, lack of nitrogen
Treatment options: Fertilize the lawn and improve nitrogen content in soil. Hand-pull or dig up small patches. Apply post-emergent herbicides in mid-spring to early summer or mid- to late autumn when Clover is actively growing. Learn why a fall herbicide application works.