Weed Descriptions
Part II Perennial sowthistle Sonchus arvensis
Life Cycle perennial, reproducing by seed and creeping roots; found in cultivated fields, pastures, and waste areas.
Cotyledons are ovate with a small indentation at the tip; somewhat fleshy with milky juice.
Leaves are 4 to 8 inches long, alternate, lobed, and have spiny edges.
Stems are smooth, 3 to 7 feet tall, and have a milky juice.
Flowers are borne in heads about 1 1/2 inches across; yellow. Horsenettle Solanum carolinense
Life Cycle perennial, spreading by seeds and creeping rootstocks; found in fields, gardens, and waste areas, especially those with sandy soil.
Cotyledons are lanceolate; smooth with hairs on margins.
Leaves are alternate; with dense hairs; dark green on upper surface; later leaf midribs and petioles with spines; margins undulate to sparsely toothed; petioles are short and hairy.
Stems are green to purple; erect; dense hairs; usually crooked at nodes; prickly. Horseweed (Marestail) Conyza canadensis
Life Cycle annual, reproducing by seed; found in pastures, roadsides, and wasteland.
Cotyledons are ovate and hairless.
Leaves alternate at first; entire, mostly smooth; later leaves becoming hairy; serrated margins; lanceolate; petioles are short to moderate in length; clasping; hairy on upper surface.
Stems are stout; erect; 1 to 6 feet tall; unbranched at base. Ivyleaf morningglory Ipomoea hederacea
Life Cycle annual, reproducing by seed; found in gardens, fields, and waste places; common in corn and soybean fields.
Cotyledons are butterfly-shaped, shiny, and deeply notched at the tip; the stem below the cotyledons is dull purple with a ridge running from the base of each cotyledon.
Leaves are alternate; hairy; 3-lobed and ivy- shaped; petioles are long; hairy with reddish tint.
Stems are hairy; twining and climbing or trailing on the ground. Jimsonweed Datura stramonium
Life Cycle annual, reproducing by seed; found in cultivated crops on fertile soil and especially in old feedlots.
Cotyledons are smooth and lance-shaped; prominent midrib; the stem below the cotyledon is often purplish.
Leaves are alternate; large; smooth; ovate with irregularly toothed edges; distinctive rank odor when crushed; petioles are long, pale green to purple, and may have short hairs.
Stems are smooth; thick; branching widely on upper part. Johnsongrass Sorghum halepense
Life Cycle perennial grass, reproducing by seed and large rhizomes; found especially on rich soil; common in corn and soybeans in bottomlands.
Seedling leaves are hairless; seedlings resemble young corn or grain sorghum.
Leaves are simple; smooth; alternate; 6 to 20 inches long; 1/2 to 1 1/2 inches wide; stems are erect; stout; 1 1/2 to 6 feet tall; leaf sheath hairless; no auricles; prominent, jagged, membranous ligule.
Flowers are borne in panicles that are large, purplish, and hairy. Ladysthumb smartweed Polygonum persicaria
Life Cycle annual, reproducing by seed; found in cultivated fields, waste places, and along ditches.
Cotyledons are lance-shaped with rounded tips and smooth on both surfaces.
Leaves are narrow; pointed; have smooth margins; usually with dark spot in the middle of the leaf; short petioles.
Stems are smooth; branched; sometimes hairy; clear membrane at leaf nodes.
Flowers are pink or purplish in dense erect, terminal and axillary spikes. Large crabgrass Digitaria sanguinalis
Life Cycle annual grass, reproducing by seed; found in lawns, gardens, and fields.
Seedling leaves—the first leaf is short and wide with a blunt tip.
Ligule is membranous; no auricles; medium; jagged margins; sheaths are densely hairy.
Leaves are hairy; margins often wrinkled.
Stems often root at lower nodes. Musk thistle Carduus nutans
Life Cycle biennial, reproducing by seed; found in pastures, meadows, and waste areas.
Cotyledons are lance-shaped, dull green, and have broad white veins.
Leaves smooth; light colored; very spiny margins; after stem elongation, leaf margins extend down stem.
Stems do not elongate in first year; thereafter, erect and spiny with spiny wings; 3 to 6 feet tall; lower portion branched. Peppergrass Lepidium virginicum
Life Cycle annual or winter annual, reproducing by seed; found in winter wheat, first-year pastures, and waste places.
Cotyledons lack hairs, have a peppery taste, and are unequally oval, with long petioles.
Leaves lanceolate to linear; coarsely toothed; usually lacking petioles.
Stems branched; 6 to 18 inches high; hairless or with fine hairs.
Flowers small, white, four-petaled; borne on racemes that bloom constantly, so they may show flowers on top and seed pods below. Pigweeds (Redroot, Smooth) Amaranthus species
Life Cycle annual, reproducing by seed; found in cultivated fields, fence rows, and waste places.
Cotyledons are linear and hairless.
Leaves are alternate; ovate to oval, usually with a notched tip; prominently veined; leaf tissue between veins appearing puffy and rough; younger leaves pink-tinged on bottom surface; purplish midvein; petioles are green to pink-tinged, long, and grooved on upper surface with appressed hairs.
Stems are rough; hairy; vertically ridged; branching widely if not crowded; pinkish, turning red below soil surface. Prickly lettuce Lactuca serriola
Life Cycle annual, sometimes a biennial; found in roadsides, fencerows, and wasteland.
Cotyledons are oval to spatula-shaped; the upper surface and margins are hairy.
Leaves are large, coarse, all with prickles along the margins and along the lower midribs; contain milky juice.
Flowers appear in large, terminal, pyramid- shaped clusters.
Stems are erect; 2 to 6 feet tall; stiff; hollow.
Root is a large taproot. Prickly sida Sida spinosa
Life Cycle annual, reproducing by seed; found late in the season in waste places, cultivated fields, gardens, and pastures.
Cotyledons are rounded to heart-shaped, have hairy margins, and have a shallow indentation or notch at the apex; the stem below cotyledons is covered with short, velvety hairs.
Leaves are alternate; oblong; sparsely hairy; saw-toothed margins; yellow-green; petioles are long and covered with short, gland-tipped hairs.
Stems are branching widely; softly hairy; bearing 2 to 3 short, blunt spiny projections below each node. Prostrate knotweed Polygonum aviculare
Life Cycle annual, reproducing by seeds; found in trampled areas in lawns, waste places, and along roadways or paths.
Cotyledons are united at the base to form a small cup.
Leaves are bluish-green, alternate, oblong, narrowed at the base and pointed at the tip.
Stems are bluish-green; leafy; wiry; extending 4 to 24 inches in all directions from the taproot, forming a mat; nodes are covered with thin papery sheaths. Purslane Portulaca oleracea
Life Cycle annual, reproducing by seed; found in fields and waste places.
Cotyledons are succulent, linear, and hairless; tinged with bright red; the stem below cotyledons is bright red and succulent.
Leaves are oblanceolate; fleshy; maroon on edges; opposite; smooth; petioles are short, fleshy, and flattened on upper surface.
Stems are juicy; smooth; often reddish; prostrate and ascending toward ends.
Flowers are small, star-shaped, and yellow; borne in axillary clusters. Quackgrass Elymus repens
Life Cycle perennial grass, spreading by seeds and rhizomes; found in waste places, pastures, and cultivated areas.
Seedling leaves are slightly hairy and bright green; the lower part of the stem is often pinkish brown and hairy.
Ligule is membranous and short; sheaths have lower parts with short hairs; upper parts smooth.
Leaves are rough above; sparsely hairy to smooth below; constriction often showing near tip; auricles present—a slender, clawlike structure at the base of the blade and clasping the stem.
Rhizomes are long; slender; sharp; white. Shattercane Sorghum bicolor
Life Cycle annual grass, reproducing by seed; found in cultivated fields where it reseeds itself.
Ligule is long; membranous; apical margin jagged with short hairs; sheaths are smooth to rough with membranous margins.
Leaves are finely veined; smooth to sparsely hairy; vigorous growth; bigger than most annuals.
Roots are fibrous. Shepherd’s-purse Capsella bursa-pastoris
Life Cycle annual, reproducing by seeds; found in cultivated and noncultivated areas.
Cotyledons and early leaves are oval to spatula-shaped with long petioles; cotyledons have a grainy appearance; the stem below cotyledons is dull green with some purplish tones. Leaves in a rosette are coarsely serrate and 2 to 4 inches long.
Stems are erect, 1 to 1 1/2 feet tall.
Flowers are small, white, 4-petaled; fruit is a triangular pod that contains about 20 seeds. Stinkgrass Eragrostis cilianensis
Life Cycle annual grass; found in cultivated fields and waste places.
Leaves have smooth sheaths except for hairs on upper portion; flat, smooth blades.
Stems are slender, smooth, and 1 to 2 feet tall, branched at the top; several stems arise from the crown; plant has a disagreeable odor.
Flowers are in branched panicles; spikelets are flat, containing 20 to 40 florets. Tall morningglory Ipomoea purpurea
Life Cycle annual, reproducing by seeds; found in gardens, fields, and waste places.
Cotyledons are shiny; smooth; oval with deeply indented tip and base to give a butterfly or kidney shape.
Leaves are alternate; hairy; broadly heart- shaped with pointed tip; petioles are long, hairy, and dull green to reddish in color.
Stems are hairy; twining or trailing on the ground.
Flowers are blue, purple, white, or variegated. Velvetleaf Abutilon theophrasti
Life Cycle annual, reproducing by seed; found in cultivated fields; occasionally in gardens, fencerows, and waste places.
Cotyledons can be nearly round or heart- shaped; margins are entire; cotyledons are covered with short hairs on both surfaces; the stem below the cotyledons is hairy and often purplish near the soil line. Leaves are alternate; heart-shaped with pointed tip; large; fine-toothed margins; soft, velvety hairy surface; petioles are round, covered with short, velvety hairs. Stems are covered with short, velvety hairs.
Flowers are orangish-yellow, appearing singly or in clusters in leaf axils. Waterhemp Amaranthus tuberculatus
Life Cycle annual, reproducing by seed; found in cultivated fields and waste areas.
Cotyledons are egg-shaped.
Leaves are more elongated than pigweed; no hairs on leaves; petioles are green to red, hairless, and long.
Stems are smooth and vertically ridged.
Flowers are small, greenish, and surrounded by small bracts; seed head is less compact and more branched than most pigweeds. Wild carrot Daucus carota
Life Cycle biennial, reproducing by seed; found in pastures and roadsides.
Cotyledons are linear, long and smooth; seedling has a characteristic carrot odor when crushed.
Leaves alternate; compound; finely pinnately divided; about 5 inches long.
Stems erect; hairy; stout and branched at top.
Flowers small, white, five petaled; located in broad umbels at ends of the branches. Wild garlic Allium vineale
Life Cycle perennial, reproducing from seed, aerial bulblets and underground bulbs; found in grain fields and pastures. Leaves are slender; round; hollow; attached at the bottom half of the stem.
Stems are 1 to 3 feet tall; smooth and waxy.
Flowers are small, greenish-white; borne on short stems above aerial bulblets at top of stem. Wild mustard Brassica kaber
Life Cycle annual or winter annual, reproducing by seed; found in grain fields and occasionally in other cultivated crops.
Cotyledons are kidney-shaped and smooth.
Leaves vary in length; 2 to 8 inches long; 1 to 4 inches wide, larger at bottom; lower leaves irregularly lobed, toothed, petioled, and with bristly hairs; upper leaves smaller, often not lobed, alternate, and with short or absent petioles.
Stems erect; branched near top; with a few bristly hairs.
Flowers bright yellow; four-petaled; clustered at ends of branches. Wild parsnip Pastinaca sativa
Life Cycle biennial, reproducing by seed; found in pastures and waste areas.
Leaves are alternate; pinnately compound; have sawtoothed edges.
Stems (second year) erect; hairy; grooved; 2 to 5 feet tall.
Flowers small; yellow; five petaled; located in umbels at the top of stems and branches. Wild sunflower Helianthus annuus
Life Cycle annual, reproducing by seed; found in cultivated fields, pastures, and waste places.
Cotyledons are oval.
Leaves are alternate; simple; hairy; saw-tooth margins; petioles are short to moderate in length.
Stems are erect; very coarse; 2 to 10 feet tall.
Flowers are composed of yellow ray flowers surrounding brown or reddish-brown disk flowers; flower heads 1 to 5 inches in diameter. Woolly cupgrass Eriochloa villosa
Life Cycle annual grass, reproducing by seed; found on moist soils in corn, soybean, small grain, and forage crops.
Ligule has a fringe of hairs; sheaths are covered with very short, dense hairs.
Leaves are covered with very short, dense hairs; one margin tends to be wrinkled; first leaf is broad and is shaped like a thumb.
Inflorescences of several racemes; woolly with hairs; spikelets in two rows on one side of rachis. Yarrow Achillea millefolium
Life Cycle perennial, reproducing by seeds and underground rhizomes; found in pastures and waste places.
Cotyledons are club-shaped with prominent veins.
Leaves soft; hairy; finely divided; bluish green; aromatic; fernlike.
Stems are 1 to 2 feet tall; branching at the top; covered with gray-green hairs; multiple stems may rise from each crown.
Flowers borne as small, white ray flowers surrounding yellow disc flowers in flat-topped clusters at the ends of branches. Yellow foxtail Setaria glauca
Life Cycle annual grass, reproducing by seed; found in all places except woods.
Seedling leaves are arched and hairless; the base of the seedling is often reddish.
Ligule is a fringe of hairs; sheaths are flattened and smooth with purple to reddish bases.
Leaves are smooth except for long hairs near ligule on upper surface.
Stems are erect; 1 to 2 feet tall.
Flowers are borne in a terminal panicle which is dense and erect. Yellow nutsedge Cyperus esculentus
Life Cycle perennial sedge, reproducing by seeds and tubers; found primarily on damp soils; often troublesome in cultivated fields.
Seedling yellow nutsedge resembles grass and is often overlooked; seedlings are rarely produced in nature.
Leaves are 3-ranked; smooth and shiny; basal; greenish-yellow; triangle-shaped in cross section.
Stems are erect; triangular in cross section.
Rhizomes are short with scales or ridges; tubers at ends. Yellow woodsorrel Oxalis stricta
Life Cycle perennial or annual, reproducing by seed; found in pastures, lawns, and waste places.
Cotyledons are an elongated oval; the stem below cotyledons is very short, making the seed leaves appear to emerge from the soil.
Leaves have long petioles; divided into three heart-shaped leaflets.
Stems are weak, prostrate or semi-erect; may root at joints; smooth and hairy; 4 to 18 inches tall; often multibranched.
Flowers small; yellow; five petaled; occurring in clusters. BACK