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Alfalfa

Problematic Weeds in Alfalfa

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Fall planting

  • Burclover
  • Curly dock
  • Goosegreass
  • Persian speedwell
  • Poison hemlock
  • Swinecress
  • Thymeleaf speedwell

Spring planting

  • Bermudgrass
  • Dandelion
  • Dodder species
  • Field bindweed
  • Johnsongrass
  • Nutsedge

The following weeds may cause stand establishment problems or be problematic long term due to ineffective herbicide control options. If your proposed alfalfa site is infested with any of these weeds, you should either consider managing these weeds before you plant or choose a different site. If you observe infestations of these weeds in your current alfalfa field, you can rotate to a different crop for more successful management. Names link to more information on identification and biology.

Click on photos to enlarge

Avoiding fields with weed infestations—Fall planting

Seedlings/young plant Mature plant

Seedling of California burclover
Burclover
(Medicago polymorpha): Pea family; summer annual. Seed leaves oblong; first true leaf rounded with single leaflet; later leaves with characteristic clover-like shape.

Leaves and flowers of California burclover.
Burclover
(Medicago polymorpha): Pea family; summer annual. Trifoliate leaves resemble those of clover and usually have reddish-tinged midveins. Small, bright-yellow flowers form in clusters at the end of stems.

Curly dock seedling
Curly dock
(Rumex crispus): Buckwheat family; perennial. Seed leaves succulent and 3 times longer than wide; young seedlings vary in color, from entirely green to red-tinged in cooler months; petioles of young seedlings ribbed with bases extending onto stem.

Mature curly dock
Curly dock
(Rumex crispus): Buckwheat family; perennial. Mature plant with characteristic jointed stems, a membranous sheath at the leaf base, and usually swollen nodes; can be 2 to 5 feet tall.

Seedling of goosegrass
Goosegrass
(Eleusine indica): Grass family; summer annual. Ligule thin, membranous and appears torn; collar region with a few sparse hairs; no auricles; leaf blades smooth and folded.

Goosegrass
Goosegrass
(Eleusine indica): Grass family; summer annual. Appears as a whitish, silvery mat, forming a pale green clump with flattened stems in a low rosette; leaves with a short membranous ligule—blades are flat or folded and 1/8 to 1/3 inch wide.

No photo available
Persian speedwell  
(Veronica persica): Figwort family; winter annual; seed leaves are oval to triangular in shape and almost as long as they are broad; although similarly shaped, the first true leaves are larger and either shallowly toothed or smooth around the edges.

Persian speedwell
Persian speedwell
(Veronica persica): Figwort family; winter annual; leaves are roundish or oval; upper leaves arranged alternately along the stem; lower leaves arranged in pairs; small, deep blue flowers with white centers are borne on stalks, 3/8 to 1 inch long; entire plant is covered with hairs; mature plants low growing when mowed frequently.

Poison hemlock seedling
Poison hemlock
(Conium maculatum): Carrot family; biennial. Seed leaves light green, 3 to 5 times as long as wide, with prominent veins underneath; first true leaves smooth and deeply cut 2 to 3 times like a parsley leaf; when crushed has parsnip-like odor.

Poison hemlock
Poison hemlock
(Conium maculatum): Carrot family; biennial. Leaves are divided 2 to 3 times into deep lobes or toothed segments; lower leaves have short stalks, flattened at the base that partially envelop stems; stems have purple markings upper leaves have short stalks or are stalkless; white sepaless flowers are borne on umbrella shaped clusters.

Swinecress
Swinecress
(Coronopus didymus): Mustard family; winter annual; seed leaves light green, narrow, long, widest at tip; first true leaves club shaped with two notches (teeth) around margin; leaves and stems slightly hairy; distinct skunk-like odor.

Swinecress
Swinecress
(Coronopus didymus): Mustard family; winter annual; leaves divided into narrow segments, somewhat hairy, and may be toothed; lower leaves grow on short stalks; upper leaves sessile; stems branching and prostrate; flowers white and tiny; seed pods deeply wrinkled and develop 2 lobes when mature.

Thymeleaf spedwell
Thymeleaf speedwell
(Veronica serpyllifolia): Figwort family; perennial; seed leaves spatulate to oblong; first true leaves opposite, entire, sessile, and lack hairs; older leaves can be more elliptic or ovate in shape and regularly dentate.

Thymeleaf speedwell
Thymeleaf speedwell
(Veronica serpyllifolia): Figwort family; perennial. Lower leaves opposite, oval to roundish, on short petiole, with smooth or fine-toothed margin and often 3-veined from the base; upper leaves alternate, sessile, and smaller, oval to elliptic; stems almost entirely creeping; small white to pale-blue flowers with darker blue lines, borne on stalks.

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Avoiding fields with weed infestations—Spring planting

Seedlings/young plant Mature plant

Seedling of bermudagrass
Bermudagrass
(Cynodon dactylon): Grass family, perennial. First leaves with somewhat rough surface; ligule present; tuft of long hairs on either side of ligule; stem flat, wiry, and without hairs.

Bermudagrass
Bermudagrass
(Cynodon dactylon): Grass family, perennial. Look for dense mats with spreading and branching stolons that root at nodes.

Dandelion seedling
Dandelion
(Taraxacum officinale): Perennial. Seed leaves green-yellow, smooth, ranging from circular to oval to spatulate; young leaves without hairs and usually gray-green on lower surface, alternate, form basal rosette, and spatulate or oval with long petiole; margins of third true leaf wavy with irregular, widely spaced teeth.

Mature dandelion plant.
Dandelion
(Taraxacum officinale): Perennial. No visible stem; leaves with deeply serrated margins, cluster in rosette at plant base; flowering stalks 6 to 24 inches long and terminate in a compound inflorescence; seeds enclosed singly within fruiting bodies, attached to a long slender stalk that terminates in a parachute-like structure.

Pale seedling roots and orange stems of dodder
Dodder species
(Cuscuta spp.): Morningglory family, summer annual. Leafless or with small scalelike triangular leaves about 1/16-inch in length; stems slender, twining or threadlike; vary in color from pale green to yellow or bright orange.

Dodder flowers and seed capsules
Dodder species
(Cuscuta spp.): Morningglory family, summer annual. Flowers bell-shaped, cream colored and small (about 1/8-inch long); usually occur in clusters but occasionally borne singly.

Seedling of field bindweed
Field bindweed
(Convolvulus arvensis): Morningglory family; perennial; seed leaves nearly square, with shallow notch at tip; early true leaves spade shaped; petioles flattened.

Field bindwwed
Field bindweed
(Convolvulus arvensis): Morningglory family; perennial; leaves are spade or bell-shaped, lobed at base, and attached to flattened petioles; stems trail on ground or climb on upright plants; trumpet-shaped white to purplish flowers close each afternoon and reopen the following day.

Johnsongrass 
					seedlings.
Johnsongrass
(Sorghum halepense): Grass family; perennial; first leaves with white midvein, 8 times longer than wide and rolled in bud; ligule membranous below and fringed or toothed above; no auricles.

Johnsongrass
Johnsongrass
(Sorghum halepense): Grass family; perennial; leaves have prominent whitish midvein, which snaps readily when folded over; flower head is large, open, well-branched, and often reddish tinged; grows in spreading, leafy patches that may be as tall as 6 to 7 feet.

oung yellow nutsedge plant
Nutsedge
(Cyperus spp.): Sedge family; perennial.
First leaves inconspicuous and grasslike; grow mainly from tubers or "nutlets" formed on rhizomes, mostly in upper foot of soil.

Flowering yellow nutsedge plant.
Nutsedge
(Cyperus spp.): Sedge family; perennial.
In cross section, leaves V-shaped, arranged in sets of three at base, and stems triangular.

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