Cogongrass

Plant: Aggressive exotic, colony-forming perennial grass, often in circular infestations, 1-4 ft (30-120 cm) tall, often leaning into mats when over 3 ft (105 cm) tall, clumps of long leaves, often yellowish-green, silver plumed flowers in spring, arising from sharp-tipped white-scaly rhizomes.

Stem: Upright to ascending, stout, not apparent and hidden by overlapping leaf sheaths.

Leaves: Mainly from near the base, with overlapping sheaths, long-lanceolate, 1-4 ft (30-120 cm) long and 0.5-1 in (12-25 mm) wide and shorter upward, narrowing at base and with a sharp tip often drooping, often yellowish-green, white midvein on upper surface with midvein slightly to mostly off-center (varies in an area), blades flat or cupped inward, margins translucent and minutely serrated (rough), outer sheaths often long hairy and hair tufts near the throat, ligule a fringed membrane to 0.04 in (1.1 mm) long.

Flowers: Feb-May (or year-round in FL). Terminal, silky spike-like panicle, 1-8 in (3-20 cm) long and 0.2-1 in (0.5-2.5) cm wide, cylindrical and tightly branched, spikelets paired, each 0.1-0.2 in (3-6 mm) long, obscured by silky to silvery white hairs to 0.07 in (1.8 mm) long.

Seeds: May-Jun. Grain brown, oblong, 0.04-0.05 in (1-1.3 mm) long, released within silvery hairy husks for wind dispersal.