Upright Primrose Willow

(Ludwigia decurrens)

Upright Primrose Willow (Ludwigia decurrens  Walt.)

Identification: Flowers yellow, with 4 petals and 8 to 12 stamens. Stigma undivided. Sepals narrow, elongate, pointed, alternating with the petals, and straight, not curling downward. Seed capsule elongate, not square at the bottom. Flowers and seed capsules on long flower stalks, nearly equal in length to the leaves. Leaves elongate, alternate, with smooth outer margins, and short to absent petioles. Plant 1 to 2 feet in height.

Distribution: Wisconsin and Illinois in the west to Pennsylvania in the east, southward to Florida and Texas.

Habitat: Upright Primrose Willow is found in ditches, swamps, and the edges of ponds.

Flowering period: July to September.

Similar Species: Creeping Primrose Willow has 5 petals, not 4. Seedbox has 4 petals, but only 4 stamens, the sepals are broader, and the stem is not square.