Alligator Flag also known as Fire Flag, Thalia geniculata, is a large plant that grows in swamps and wet ditches. It blooms from summer to fall.

Alligator flag’s large elongated leaves are held on long stalks. The leaves are broadly lance-shaped, with broadly rounded bases. They can be up to eight inches wide and more than 2 1/2 feet long. Several leaves growing together are sheathed at the base. Alligator flag flowers are paired; that is, two flowering bracts emerge on top of a tall flower stalk as multiple small purple flowers that hang from the bracts. The flowers have three petals.

This plant is a large spreading or colonizing plant great for restorations or larger areas in wet conditions or shorelines.