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Corn

Summer Annual Weeds

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  • Barnyardgrass
  • Black nightshade
  • Common lambsquarters
  • Common purslane
  • Hairy fleabane
  • Groundcherries
  • Hairy nightshade
  • Horseweed
  • Junglerice
  • Annual morningglories
  • Palmer amaranth
  • Redroot pigweed

The weeds shown here may be seen in spring-planted corn seedlings. For weeds in fall-planted corn seedlings, see common winter weeds. Names link to more information on identification and biology.

Click on photos to enlarge
Seedling of barnyardgrass, 
				Echinochloa crus-galli.
Barnyardgrass
(Echinochloa crus-galli): Grass family; summer annual; first leaf dull gray green; stem flattened, purplish; no ligule.
Black nightshade seedling.
Black nightshade
(Solanum nigrum): Nightshade family; summer annual; seed leaves oval and pointed; first true leaves spade shaped with smooth edges; lower surfaces often purple; petioles stems and leaves with some hairs.
Seedling of common lambsquarters.
Common lambsquarters
(Chenopodium album): Goosefoot family; summer annual; seed leaves are narrow, with nearly parallel sides; seed leaves and early true leaves dull blue-green above and often purple below.
Seedling of common 
					purslane, Portulaca oleracea.
Common purslane
(Portulaca oleracea): Purslane family; summer annual; seed leaves oblong, somewhat club shaped, succulent, maroon on lower surface, and green or maroon on upper surface; young leaves smooth, succulent, oblong, green on upper surface, maroonish underneath, and broadest around leaf tip, with short petioles.
Seedling of hairy fleabane.
Hairy fleabane
(Conyza bonariensis): Sunflower family; summer annual; seed leaves gray green; first leaves narrow and covered with short, soft hairs; often wrinkled or distorted.
Tomatillo groundcherry seedling.
Groundcherries
(Physalis spp.): Nightshade family; summer annual or perennial; seed leaves yellow green to gray green; first leaves oval to triangular, with smooth or slightly wavy margins, and a strong odor when crushed.
Hairy nightshade seedling.
Hairy nightshade
(Solanum physalifolium=Solanum sarrachoides): Nightshade family; summer annual; seed leaves narrow, small, and lance shaped with very short soft hairs along edges; first true leaves with wavy edges and prominent veins.
Seedling of horseweed.
Horseweed
(Conyza canadensis): Sunflower family; summer annual; seed leaves dull green, oval with fine hairs, and with short stalks that sometimes may be tinged brown-purple; first true leaves covered with hairs on upper surface and margins; undersides of early leaves smooth.
Seedling of junglerice.
Junglerice
(Echinochloa colona): Grass family; summer annual; grayish, dull green first leaves; several purple bands on surface of leaf blade; no ligule, no auricle.
Seedling of 
				annual morningglory, Ipomoea sp.
Morningglories
(Ipomoea spp.): Morningglory family; summer annual; seed leaves deeply notched; heart-shaped first true leaves with deep lobes at base; stem below seed leaves maroon at base and green toward leaf tip.
Mature plant of Palmer amaranth.
Palmer amaranth
(Amaranthus palmeri): Pigweed family; summer annual; cotyledons are long and narrow and often red underneath; true leaves are alternate, oval-shaped, and notched at the tip.
Redroot pigweed seedlings.
Redroot pigweed
(Amaranthus retroflexus): Pigweed family; summer annual; seed leaves long and narrow with red undersides; first true leaves with notched tips and much broader than seed leaves.

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