Alligatorweed

Alligatorweed

Alternanthera phyloxeroides

Amaranthaceae (Pigweed Family)

▲ ▼ infestation at Black Bayou, near Monroe, LA

▲ ▼ flowering stems

▲ ▼ inflorescences

Alternanthera phyloxeroides (Mart.) Griseb.; Alligatorweed: (Bayer Code: ALRPH; US Code ALPH)

Warm-climate terrestrial to aquatic creeping perennial weed with spreading growth habit; produces stolons
Leaves opposite, lanceolate, usually with pointed tips, hairless to with short hairs
Flowers tiny, paper-like, white in globe-shaped clusters at tips of flowering stalks 0.4 to 2 inches long (sometimes longer)
Problematic aquatic weed in warmer climates

(Updated January 15, 2019)