Common lawn weeds found in Central Maryland

For lawns, there are three basic types of weeds: grassy type weeds, grass-like weeds, and broad leafed weeds. Each require a different method for control.

Some common lawn weeds are annuals. Sprouting from seeds, they develop, blossom and form new seeds, then die in the fall, repeating the process each year. Crabgrass is one such weed. Once these types of weeds take root, they are difficult to remove without harming the lawn. The ideal control prevents them from developing in the first place.

Pre-emergent Weed Control applied in the spring stops many weed seeds from germinating. The soil's surface is covered with a microscopic protective layer that prevents any germinating seeds from taking hold, including crabgrass. If left undisturbed, this protective layer will maintain its defensive qualities throughout the prime germinating period. This is when most weed seeds will normally start developing. Of course, there is no 100% guarantee that additional seeds won't be carried in by winds, birds, or any number of other methods.

A lawn full of weeds signals more problems than just weeds. Most weed problems are related to the top soil's health and condition, and the vitality of the turf grass.

Soil problems usually fall into several categories:

• Lack of soil nutrients

• Soil Compaction

• Thick thatch layer

• Inadequate water, or too much moisture

• Too much shade for the turf grass to develop

One or more of the above problems will cause an abundance of lawn weeds

Weed seeds exist in every soil by the thousands per square yard. The reason you don't see thousands of weeds is because they must have the right conditions to sprout. Often all the weed seeds need is a little moisture and sunlight! Sunlight is the key. A thin lawn allows plenty of light to reach the soil. A thick lawn blocks that light.

When you have soil problems, you reduce the vitality of your lawn's health. It slows the vigorous growth normally associated with a healthy turf grass. The lawn begins thinning out and when this happens, more sunlight reaches the soil and creates the right environment for weeds to take root.

Annual Bluegrass: grassy weed (also called winter grass, poa annua, speargrass) is capable of growing at mowing heights lower than 1/4".
Barnyard Grass: annual grass reaching 1' - 4' in height. Leaves are smooth and light green in color.
Buckhorn Plantain: forms a spreading or upright basal rosette of narrowly oval leaves that grow above a long, sturdy taproot with lateral branches.
Carolina Geranium: produces a deep taproot. Flowers have five pink to lavender petals. Seeds have a conspicuous cranesbill beak about 1/2" long.
Carpet Weed: a summer annual with a short taproot. Seeds lie dormant over the winter and sprouts slowly in the spring. Once it sprouts it grows rapidly in the summer heat.
Chickweed: Chickweed is a prolific spring weed as it thrives under cool, wet conditions. Other common names for chickweed include starweed, winterweed, satin flower and tongue grass.
Crabgrass: a warm season annual grass which grows best in the heat of midsummer when desirable lawn grasses are often semi-dormant and offer little or no competition. Crabgrass over winters as seed, comes up about mid-May or later, and is killed by the first hard frost in fall.
Dandelion: are a persistent weed problem. Each seed head of a mature plant produces thousands of weed seeds that float easily in the breeze.
Foxtail Grass: sometimes confused with crabgrass, foxtails (also called wild millet) produces a large robust seed head. Its texture is coarse and forms tufts in mowed lawns. Foxtails usually germinate after crabgrass and before goosegrass.
Goosegrass: an annual that grows as a compressed plant in turf. Leaves are distinctly folded and may be smooth or have a few hairs. It's found in a wide range of settings, but tolerates compacted, dry areas where desirable turfgrasses have thinned out.
Ground Ivy: low-growing, perennial invader of lawns, vegetable gardens, and flower beds. It thrives in moist, shady areas, as well as sunny locations. The scalloped leaves are round or kidney-shaped and are attached by petioles to square stems.
Henbit: responsible for painting many lawns with a pinkish purple in the early spring. Henbit actually sprouts from seed planted from the previous springs crop in the fall.
Lambsquarters: usually found in low-maintenance turf situations. Proper mowing will usually control lambs quarter due to its upright growth habit. It establishes easier in spring-seeded cool-season turf that enters the summer in a thin state.
Mushrooms/Toadstools: appear in lawns during wet weather in spring and summer. Mushrooms live on organic matter such as roots, stumps and boards in the soil. Most don't harm the lawn but are unsightly.
Nutsedge: is a common weed found in many home lawns. The color, growth habit, and rapid growth rate make yellow nutsedge a prominent distraction in the aesthetics of high quality lawns.
Plantain: a common broadleaf lawn weed. It is a cool-season perennial weed found practically in any habitat. The leaves are arranged in a rosette pattern with prominent veins.
Sorrel: also called yellow oxalis, sheep sorrel and yellow sour grass. Common wood sorrel is a plant from the Oxalis genus. It flowers for a few months during the spring, with small white flowers with pink streaks. Red/violet flowers occur, but rarely. The binomial name is Oxalis acetosella, because of its sour taste.
Wild Violets: include several cool-season annuals and perennials with low-growing habits. These species are very shade tolerant and prefer lawns located on moist, fertile soils. Violets tend to be most visible during cool weather of spring and fall.