One of the most frustrating problems with growing a lawn is managing weeds. Besides making a lawn look unattractive and unkempt, lawn weeds can complete with grass for nutrients and moisture. Although homeowners battle many different types of weeds, some of them are more common than others. It’s important to properly identify a particular weed in order to determine how best to control it.
Crabgrass (Digitaria spp.) is one of the most typical lawn weeds. The two main crabgrass types are smooth crabgrass and hairy crabgrass. Although they’re similar in appearance, the hairy variety has hairs on its leaf, while the other one doesn't. Both are annuals, are coarse in texture and sprout sometime in May. Because crabgrass grows close to the ground, it can escape a lawn mower. Use a crabgrass rake to control lighter populations.
Goosegrass (Eleusine indica (L.) Gaertn) lawn weeds resemble the shape of a wagon-wheel and have a white center. They need light and moisture to germinate, do well in compacted soils and mostly compete with turfgrass in thin lawns subjected to heavy traffic. This weed germinates at least two weeks after crabgrass appears. Although the herbicide, Dimension (dithiopyr), can help control goosegrass, don’t use this chemical under dry, hot conditions as it’s volatile.
Common chickweed (Stellaria media), a herbaceous, broadleaf annual, is a spring weed that loves wet, cool conditions. It has smooth, egg-shaped leaves and tender, branching stems. Chickweed flowers grow singularly in small clusters. Their reddish-brown seeds are flat and circular. Because chickweeds form a thick vegetation mat, they can’t be eliminated by close mowing. Use timely applications of pre-emergent herbicides such as Simazine and others.
Dandelions (Taraxacum officinaleare) are perennials with fleshy, dense taproots that are able to penetrate 2 feet or more into soil. The top part of the weed has a rosette of leaves that arise from the plant’s crown. It's known for its bright yellow, round flowers that grow on a stalk and a seed-head that resembles a puffball of seeds. Control small populations of dandelions by digging or pulling them out. Applying a herbicide is another control method.
Annual bluegrass (Poa annual) is a bright-green grass that grows vigorously in cool, moist weather. It produces numerous weed seed heads. Patches formed by annual bluegrass can quickly die out with the arrival of hot, dry weather. Control the weed with Glyphosate and use Dacthal in late spring or early fall for any pre-emergence management, advices the University of Delaware Cooperative Extension.