Weeds, Perennial

Use the photos below to identify weeds in the field. Names link to more information on identification and biology.

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Bermudagrass (Cynodon dactylon): Grass family; perennial; first leaves with somewhat rough surface; ligule surrounded by ring of hairs with tuft of long hairs on either side; auricles absent; stem flat, wiry, and without hairs.	Field bindweed (Convolvulus arvensis): Morningglory family; perennial, with most new shoots and seedlings emerging in spring; seed leaves nearly square, with shallow notch at tip; early true leaves spade shaped; petioles flattened.	Johnsongrass (Sorghum halepense): Grass family; perennial; persists and spreads via underground stems (rhizomes), which are thick, fleshy, and segmented; roots and shoots can rise from each rhizome segment; leaves have a prominent whitish midvein.
Sedges (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; in cross section, leaves V-shaped, arranged in sets of three at base, and stems triangular.	Swamp smartweed (Polyognum coccineum): Buckwheat family; perennial; leaves are alternate, oblong, and taper at each end; enlarged nodes and prominent sheath.	Common knotweed (Polygonum arenastrum): Seed leaves are long, very narrow, rounded at the tip and light green with a white cast. The true leaves are much broader, emerging from an encircling, membranous sheath at the leaf base.