Long-leaved willow primrose

Family: Onagraceae
Scientific name: Ludwigia longifolia
Description: Plant Form: Erect annual shrub. Size: Up to 3 m tall. Stem: Hairless, square shaped, often with winged edges. Many branched towards top. Green or reddish becoming rounded and woody with age. Leaves: Stalkless, glossy, alternate along stem, elongated lance-shaped, 5-35 cm long. Flowers: Single and yellow, between leaf and stem, with 4 or 5 petals with prominent veins. Fruit and Seeds: Becoming light brown as they mature, sharply 4-angled with large numbers of tiny seeds in 4 sections. Habitat: Waterways, wetlands, swamps, drains, riverbanks. Distinguishing Features: Less hairy stems, leaves and fruit than native and other invasive Primrose willows (Ludwigia species).

Example images for this weed