Use the photos below to identify weeds
in the field. Names link to information on
identification and biology.
Click on photos to enlarge
Black nightshade
(Solanum nigrum): Nightshade family; summer annual or short-lived perennial;
seed leaves oval and pointed; first true leaves spade shaped with smooth edges;
lower surfaces often purple; petioles stems and leaves with some hairs. |
Hairy nightshade
(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. |
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. |
Common cocklebur
(Xanthium strumarium): Sunflower family; summer annual;
seed leaves bright green, shiny on upper surface, pointed, and
about 6 times longer than wide; true leaves on seedlings notched
on margins and taper to leaf tip; bur may remain attached to
base of seedling. |
Annual
sowthistle
(Sonchus oleraceus): Sunflower family; summer or winter annual; seed leaves
markedly stalked, almost spoon-shaped, rounded at tip and often have grayish
powdery bloom; injured tissue bleeds milky white latex. |
Common
sunflower
(Helianthus annuus): Sunflower family; summer annual;
seed leaves oblong, joined at base, smooth; first true leaves opposite,
elliptical, dull green, covered with short bristly hairs rough
to the touch; later leaves alternate, elliptical to lance shaped. |
Kochia
(Kochia scoparia): Goosefoot family; summer annual; seed leaves
linear to narrowly lance shaped, smooth; true leaves narrowly
lance shaped, gray-green, covered with soft white hairs, forming a small
rosette. |
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; young leaves have mealy appearance from coating
of fine translucent granules. |
Russian thistle
(Salsola tragus): Goosefoot family; summer annual; cotyledons and first
true leaves long and thin; first leaves are fleshy, soft, and weakly spine-tipped;
stems slender and flexible, often with reddish purple striations along their
length. |
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. |
Common knotweed
(Polygonum arenastrum): Knotweed family; annual or short-lived perennial,
germinates during fall or spring; seed leaves are long, very narrow, rounded
at the tip and light green with a white cast; true leaves are much broader, emerging
from an encircling, membranous sheath at the leaf base. |
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. |
Longspine sandbur
(Cenchrus longispinus): Grass family; summer annual; seedling leaves are
flattened, have a purplish tinge at the bottom; distinctive identification characteristic
is the bur, from which the young plant emerges, found by digging carefully around
the roots. |
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