GROWTH HABIT: Perennial, erect to 8 feet tall, associated with moist or marshy areas.
LEAVES: Simple, lance-shaped, smooth margins, opposite or whorled.
STEMS: Branched, terminating in flowering stalks.
FLOWER: Rose-purple flowers having 5 to 7 petals and numerous stamens, in long, vertical recemes.
ROOTS: Large, fleshy, adapted to aquatic sites.
OTHER: Dense infestations can impede water flow in canals and ditches.