A perennial weed is any weed capable of surviving for three or more years Perennial weeds are characterized by vegetative reproduction. Perennial weeds may or may not reproduce by seed. They always, however, have the potential to reproduce by vegetative means. Description of Swamp Smartweed Swamp smartweed has erect stems 1 to 3 feet tall with enlarged nodes.
Stems are usually unbranched.
Leaves are 2.5 to 8 inches long, pointed at the tip with a rounded base, and have prominent veins. A papery sheath, called the ochrea, surrounds the stem at the base of each leaf. Flowers are rose and are found in a compact erect spike 1 to 3 inches long. Seeds are oval, flattened on one side, black, shiny, and slightly rough. The plant reproduces by seed and by tough, woody, horizontal rootstocks.