Weed Control

Eleusine indica

Goosegrass is a summer annual that grows as a compressed plant in turf with stems radiating outwards from a central, distinctive white center. It appears as a whitish silvery mat, forming a pale green clump with flattened stems in a low rosette. Leaf blades are folded along the midvein, are 2-14 inches long and 3-8 mm wide, and have little to no hair. Sheaths are flattened, whitish at the base, and sparsely hairy in the collar region. Short, stiff seedheads, composed of 2-13 spikes each, occur in clusters at the top of stems. Two rows of flattened spikelets occur along each spike. Each spikelet contains 3-6 light brown to black seeds that are 1-2 mm long. Goosegrass is normally found in compacted areas or areas of heavy wear; it can produce seed even when closely mowed. The distinctive white center of goosegrass distinguishes it from most other grass weeds.

Kyllinga brevifolia

Green kyllinga is a perennial sedge that grows in continuously enlarging patches. Kyllinga grows well in warm weather and is usually found in damp or wet areas. It grows in a prostrate manner, reaching a height of 15 inches, and produces a network of numerous underground rhizomes. It roots and sends out leaves at each stem node. Leaves are long and narrow, tapering to a point and ranging from 1 to 6 inches in length. Leaves have a distinct ridge along the midvein and no hairs, auricles or ligules are present. Flowering usually occurs from May to October, producing flower stalks that are triangular in cross section and 2 to 8 inches in length. Flowers are round, green and about 3/8 inch in diameter. Directly below the flower is a group of three leaves that radiate out from the stalk. There are 30 to 75 spikelets within each flower and each one is capable of producing one seed. Once a few plants become established in turfgrass or ornamental areas, spread can be rapid. In warm weather, rhizomes can grow more than 1 inch per day, forming thick mats in just a few weeks.

Cardamine hirsuta

Hairy bittercress is primarily a summer annual but occasionally a winter annual weed. Flowers occur in clusters and are usually small (2 to 3 mm) with 4 white petals. Distinct characteristics of hairy bittercress are the siliques that can explosively spread the seed up to 10 feet from the parent plant. Stems are erect, branched at the base, and can reach 12 inches in height. Leaves consist of 2 to 4 pairs of round leaflets that are arranged alternately along the central leaf stem. Upper leaves are smaller and have more hair than lower basal leaves.

Lamium amplexicaule

Henbit is a winter annual that reproduces by seed and rooting stems. Stems of henbit droop and then turn upright to grow up to 16 inches tall. Stems may root where they touch the ground. They are square, green to purplish, and smooth or hairy. The roots are fibrous. The 1/2 to 1 inch long leaves of henbit are opposite and have dark green coloring above the lighter green below. The leaves are ovate to circular and leaf edges have rounded teeth with crinkled edges. The henbit flowers are tubular, pink to red or purple, and are up to 3/4 inch long. Henbit normally flowers April to June and occasionally in September. It is often found growing in moist, fertile soils.

Trifolium campestre

Hop clover is classified as an annual herbaceous plant that is also a stipulate. The plant is three-leaved and can be found between April and October. The terminal leaflet is distinctly stalked, unlike other clovers. Petioles are usually shorter than the toothed leaflets. The shape of the leaves range from circular to oval. Stems are erect and measure 10 to 30 cm long. The plant has many branched stems with a hairy texture. Hop clover produces 20 to 40 flowers per head and each flower is stalked. The species thrives in temperate regions and does not do as well in dry or hot humid climates.

Pennisetum clandestinum

Kikuyugrass is a prostrate perennial grass that grows best under cool to warm temperatures (60° to 90°F) and moist conditions. It grows rapidly during periods of high light intensity and warm temperatures but also maintains steady growth at cooler temperatures. When growing rapidly, kikuyugrass is capable of exceeding 1 inch per day. Flowering begins in late spring and is stimulated by mowing. Seed production continues throughout summer and fall. Kikuyugrass spreads by producing a network of thick, fleshy stems. These stems often form a thick mat or thatch above the soil surface or a network of underground stems from 1 to 4 inches deep in the soil. If the stems are chopped into small pieces, each section is capable of producing new shoots and roots from its nodes. Thus, kikuyugrass can easily be moved from one area to another on mowing or renovation equipment. Leaves of kikuyugrass are light green in color and range in length from 1 to 10 inches. Pointed leaf tips and flat leaf blades are approximately 1/8 to 1/4 inch wide.

Scleranthus annuus

Knawel is usually a winter annual but occasionally a summer annual. The species has a taproot and a fibrous root system. Cotyledons are linear in outline and less than 1 mm wide with a sharp tip. Stems grow prostrate along the ground, are branched and form dense mats outward from a central plant. Flowers are inconspicuous, green in color, and somewhat spiny. Flowers also occur in clusters that arise from the position between the leaf bases and the stem. Knawel's identifying characteristics include small, linear leaves and a lack of hair on the leaves and stems.

Digitaria sanguinalis

Soliva pterosperma

Lawn burweed is a low-growing, freely branched winter annual. Leaves are opposite, sparsely hairy and twice divided into narrow segments or lobes. Flowers are small and inconspicuous. Lawn burweed fruits are primarily clustered in leaf axils and have sharp spines. The species reproduces by seed.

Cerastium vulgatum

Mouseear chickweed is a prostrate perennial broadleaf weed with stems that root at the nodes to form dense patches. It grows prostrate but will have several upright stems, and can tolerate close mowing. Small leaves are 3/4 to 1 1/2 inches long, about 1/2 inch wide, and shaped like a narrow triangle. The leaves are dark green and hairs are prominent on the upper leaf surface and on stems. The flowers of mouseear chickweed are white and contain 5 petals which are notched at the tip.

Cyperus spp.

Sedges are annual or mostly perennial grass-like plants with aerial flower-bearing stems. In annual forms, the stem can be alone or, more often, grouped with basal leaves. Perennial forms have a thick rootstock or an erect to horizontal underground rhizome usually with shortened internodes. Sedges usually have triangular stems with leaves arranged in groups of three and are similar to grasses in many attributes. Sedge species may be found in a wide range of conditions, ranging from very wet to dry and in many soil types. In sedges, as well as grasses, the seedhead will be produced at the end of an aerial, erect stem. This three-sided stem is usually solitary and will be tufted with basal leaves. Root systems are fibrous, including species such as yellow and purple nutsedge, which produce rhizomes and tubers. Flowers are extremely small and numerous and arranged in spikelets atop the stem.

Lolium spp.

Ryegrasses are annuals or perennials with hairless, flat leaf blades. Spikelets are widely spaced and alternate on the flowering spike. Perennial ryegrass is a permanent lawn choice in cooler climate areas, and annual ryegrass is seeded yearly and lives for one season. Both perennial and annual ryegrass can provide a green winter lawn when overseeded on warm-season grasses that go dormant in the fall or winter. Used on newly sown lawns of cool- and warm-season grasses, it acts as an erosion barrier while the permanent lawn develops and gives any area a green coverage. Turf managers often overseed bermudagrass with perennial ryegrass to provide a dense green turf during winter months. Depending on the climate, overseeded perennial ryegrass persists anywhere from 3 to 9 months. Although overseeding provides benefits, the spring transition from perennial ryegrass to bermudagrass can be troublesome and inconsistent due to heat-tolerant perennial ryegrass varieties and variable weather conditions in spring and early summer. Perennial ryegrass may survive longer into spring than is desired due to cool and wet conditions, and delay the transition of bermudagrass out of dormancy. High temperatures can result in perennial ryegrass transitioning out before bermudagrass can fill in. This may lead to poor playability and poor usability of the turf.

Oxalis stricta

Oxalis is a summer annual that can be perennial in some areas. It grows on weak stems that branch at the base and may root at the nodes. Leaves are arranged alternately along the stem, long-petiolated, and divided into 3 heart-shaped leaflets. Leaf margins are smooth but fringed with hairs. Stems are green to pink and grow more prostrate than erect, although they can reach up to 20 inches in height. The oxalis flower grows in clusters and is small and yellow with five petals. Cylindrical seed pods resembling a capsule range from 1/2 to 1 inch in length and have flat sides. These pods burst at maturity and may spread seeds several feet.

Alchemilla arvensis

Parsley-piert is a small and inconspicuous annual plant. The stem is sometimes prostrate, but usually erect, and much branched from the base. It is rarely more than 4 inches high. The leaves are of a dusky green color and wedge-shaped with deeply cut lobes. The whole leaf is less than 1/2 inch wide, narrowed into a short foot-stalk with leafy stipules, sheathing and cleaving to the footstalk. Slender, scattered hairs cover the entire plant. The pale green, small and stalkless flowers are crowded together in tufts. The plant is in bloom from May to August.

Polygonum pensylvanicum

Pennsylvania smartweed is a summer annual. The stems are smooth and reddish purple with large nodes and alternating leaves. The leaves are lanceolate with a red water mark. Growth is primarily erect with multiple branchings. The flowers of Pennsylvania smartweed are bright pink and bloom from July to October. The individual flowers are small and form dense spike-like clusters on hairy stems.

Euphorbia humistrata

Prostrate spurge is a summer annual broadleaf weed of lawns and turfgrass sites; it is mainly found in poor, drought-stressed areas. It germinates and grows well during hot, dry weather on thin soils and is often found on closely mowed sites. It reproduces by seed, which are abundantly produced throughout the summer. Germination occurs when soil temperatures warm to 60° to 65°F and can continue as soil temperatures climb to more than 90°F. Prostrate spurge develops a central taproot from which prostrate stems form a flat, extensively branched mat up to 2 feet in diameter. Leaves are opposite, ovate to oblong, slightly serrated, with a tinge of red or purple in the center. A milky sap drips from cut leaves, stems or roots. Spurge begins to germinate in late spring and continues to emerge throughout the summer.

Tribulus terrestris

Puncturevine is a warm-season, mat-forming annual weed with an extensive root system. It spreads by seed and is most often found on sandy, dry, or gravelly sites. Puncturevine produces clusters of sharply pointed burs that break apart at maturity. Leaves are finely divided into 4 to 8 pairs of leaflets, and are covered with hairs. Slender, hairy stems branch from the base and from leaf axils. Yellow flowers have 5 petals, are 1/2 inch wide, and are borne singly in leaf axils from midsummer until frost.

Lamium pupureum

Purple (or red) deadnettle is a winter annual with square stems and purple or red flowers. It spreads by seeds and belongs to the mint family. All leaves occur on short petioles, are sparsely hairy and are circular in outline with scalloped margins. Leaves are 8 to 12 mm long and dark green in color. The upper leaves of purple deadnettle are relatively triangular in outline and red to purple in color. The flowers are light purple to red in color and arranged in spirals 1 to 2 cm long. Stems branch from the base of the plant and may reach 16 to 18 inches in height.

Rumex acetosella

Red sorrel, also referred to as sheep sorrel, is a summer perennial. The leaves alternate and form a basal rosette. Older leaves are arrowhead shaped with two basal lobes attached to a petiole. Leaves formed along the stem are more elongated and usually lack the basal lobes. The margins of the leaf are smooth. The leaves become thick and fleshy over the summer months. The root of red sorrel is a shallow yellow taproot, combined with multiple rhizomes. Male and female flowers are produced on separate plants and flourish from May to September. The male flowers are yellowish green while the female flowers are reddish brown. The flowering stems of red sorrel can be one or many developing from a crown or rhizome. Red sorrel spreads by seed and rhizomes.

Erodium cicutarium

Redstem filaree is a prostrate broadleaf winter annual or biennial weed that ranges from 4 to 20 inches in height. A member of the geranium family, it has fern-like, or feathery, foliage in a rosette. The stems are reddish and there is a large, white taproot. (There is a "white stem filaree" that is very similar to the "red-stem.") Plants develop as a basal rosette. Rosette leaves occur on petioles and are hairy. Individual leaves are divided into 3 to 9 individual leaflets arranged opposite from one another. Leaflets are lanceolate in outline, deeply lobed and range from 1 1/4 to 8 inches long. Stems are often reddish in color, grow along the ground or may be ascending. Clusters of 2 to 8 flowers occur, with each individual flower occurring on a relatively long flower stalk. Individual flowers are approximately 1/2 inch wide and consist of 5 bright pink to purple petals.

Cyperus iria

Rice flatsedge is an erect annual sedge with a fibrous root system. Important identifying characteristics of the sedge include shiny, green ridged leaves and a lack of ligule, auricles, tubers and rhizomes. Seedlings are shiny, without hairs, and distinctly ridged and tougher than most grass seedlings. Leaves may be 3 to 8 mm wide and are dark green and shiny with rough margins toward the leaf tips. A membranous sheath occurs at the leaf base. Triangular stems occur in bunches and can be anywhere from 8 to 24 inches tall. Seedheads may reach 8 inches in length, are open, and are composed of several dense spikes. Individual spikes are, in turn, made up of many goldish brown spikelets that are approximately 5 to 13 mm long and 1 1/2 to 2 mm wide.

Capsella bursa-pastoris

Shepherdspurse is a winter annual, but may grow all year in cool, coastal areas. It forms a rosette with toothed or lobed leaves with few stems or basal leaves. It is part of the Mustard Family and can reach 3 inches to 3 feet in height. The heart-shaped seed pods make this species easy to recognize when mature. It has white four-parted flowers that are arranged at the end. It is capable of producing over 33,000 seeds per plant.

Digitaria ischaemum

Smooth crabgrass is a tufted, spreading summer annual plant with a fibrous root system. When unmowed, it will grow to a height of 6 inches, but it will tolerate mowing in turf at 1/4 inch and will still produce seed at this height. Stems are prostrate or lying on the ground with tips ascending up to 24 inches long, branching at lower nodes but not rooting. Leaves are smooth on both surfaces, with few hairs at the collar. Crabgrass often forms patches in lawns, and plants can grow together to form large clumps. The ligule is small and inconspicuous without prominent auricles. The seedhead has 2 to 6 branches.

Veronica spp.

There are several species of speedwell, some annuals and some perennials. Speedwell is a serious problem in turf, pastures, and alfalfa. Speedwell is an aquatic plant with light blue flowers that are usually partly in and partly out of the water. Speedwell can be found in swamps or along the banks of streams and ponds. Stems grow prostrate along the ground with the flowering tips upright. They may reach as much as 2 feet in length and are capable of rooting at the nodes. Leaves are generally oval to elliptic in outline, widest at the base and pointed at the tip. Leaves are shallow-toothed and approximately 3/4 to 2 1/2 inches long, and 1/2 to 3/4 inches wide. The flowers of speedwell occur in clusters, range from 2 to 6 inches in length and contain many 4-petaled, small, light purple to light blue flowers.

Ranunculus acris

Tall buttercup is a perennial weed characterized by erect stems and deeply lobed leaves. This species reproduces only by seeds. Tall buttercup produces a short, thick rootstalk with many fibrous, coarse, spreading roots. Young plants form a rosette. The first true leaves are hairy, round to heart-shaped in general outline, and shallowly lobed and toothed. Stems are erect, hairy, branched in the upper portion, and 1 to 3 1/2 feet tall. A single root crown generally produces several stems in a cluster. 1 inch wide flowers occur on long stalks in branched clusters at the tops of stems. The 5 to 7 petals are yellow or cream, and about 1/2 inch long. Directly below the petals are 5 hairy, green leaves. Tall buttercup contains a bitter, irritating oil called protoanemonin that is toxic to grazing livestock and other animals. The toxic oil is released when fresh leaves and stems are grazed, causing irritation and blistering of the skin and the lining of the mouth and digestive tract.

Festuca arundinacea

Tall fescue is a deep-rooted, cool-season perennial grass that grows vigorously in the spring and fall. It can adapt to a wide variety of growing conditions and its extensive root system helps it withstand drought or flooding. Stems have broad, dark green basal leaves. Leaf blades are glossy on the underside and serrated on the margins, measuring 1/2 inch wide and 4 to 24 inches long. Depending on the soil nitrogen level, leaves can be yellowish to dark green in color. Tall fescue can grow to heights of 3 to 4 feet. The endophyte fungus is closely associated with tall fescue and can cause major health problems in animals that consume the grass.

Panicum repens

Torpedograss is a perennial grass that may first be encountered as a dense colony dominant along a shoreline. It is a sod-forming grass with creeping rhizomes and upright stems reaching 2 to 3 feet in height. Leaves are long, flat and slender. Leaf blades can be 10 inches long, 1/4 inch wide and grayish green with thin hairs on upper surface. It thrives on coarse sands and wet soils and grows so aggressively that it may become a serious weed. It is used to a limited extent for pasture and erosion control along the Gulf Coast.

Abutilon theophrasti

Velvetleaf is an erect summer annual with leaves and stems that are covered with hairs. The first true leaves are alternate, heart-shaped, covered with hairs on both surfaces, and have toothed margins. Leaves gradually taper to a point and are approximately 2 to 6 inches long and wide. Leaf veins originate from a common point, and leaves emit an unpleasant odor when crushed. Stems are erect, mostly unbranched, and can reach up to 7 feet in height. Flowers are produced on short flower stalks, approximately 1/2 to 1 inch wide, and consist of 5 orange or yellow petals. Fruit capsules have 9 to 15 segments, each containing gray-brown seeds.

Diodia virginiana

Virginia buttonweed is a prostrate-growing perennial with branching hairy stems. It often has a yellowish mottling due to the presence of a virus that grows in close association with this weed. The leaves are elongated, lance-shaped and grow opposite one another on the stems, joined by a membrane. Virginia buttonweed prefers moist, wet conditions and can tolerate close mowing. The tubular flowers are white to purplish, and grow in the leaf axis along the stem. Flowers resemble four-pointed stars. Virginia buttonweed spreads by seed and plant segments.

Viola pratincola

Wild violet is a winter perennial, growing 2 to 5 inches tall. It can have a taproot or a fibrous root system, and also can produce rooting stolons and rhizomes. The leaves can vary but are usually heart shaped on long petioles with scalloped to shallow rounded margins. The flowers of wild violet range from white to blue to purple and appear from March to June. Flowers are pansy-like with three lower petals and two lateral petals on long single flower stalks.

Eriochloa villosa

Woolly cupgrass is an annual grass weed. The first true leaf of the seedling has a short, wide, pointed leaf blade that lies flat to the ground. The adult plant is dark green in color. The collar lacks auricles and the ligule is a fringe of fine hairs. The leaf blade surface is covered with short dense hairs; one edge of the leaf blade is typically crinkled. Woolly cupgrass begins to emerge in late April to early May, depending on soil temperature and moisture. It is usually the first annual grass weed to emerge in the spring. The woolly cupgrass seedhead has 2 to 8 racemes that branch from one side of the main stem. Seeds hang in two rows from the raceme. A "woolly" tuft of hair exists where the seed attaches to the raceme. Seeds shatter from mid-August through September.

Cyprus esculentus

Yellow nutsedge is a perennial from rhizomes and tubers that may reach 2 1/2 feet in height. The stems are erect, unbranched, 3-sided and triangular in cross section. Most plants arise from rhizomes and/or tubers. Leaves are 5 to 8 mm wide and do not have ligules or auricles. They are yellow to green in color with a shiny appearance and a distinct ridge along the midvein. Leaves are also produced in groups of 3 from the base of the plant and taper gradually to a sharp point. Spikelets occur at the ends of the solitary stems in a cluster where the flower stalks arise from a common point. Individual spikelets are yellow to brown in color.