Ludwigia decurrens, commonly known as willow primrose or wingleaf primrose-willow, is an annual herb native to floodplains, ditches, and wetlands in the central and eastern United States. It can reach up to 6 feet in height, with an erect form and distinctive winged stems. The leaves are linear to lanceolate, and the plant produces bright yellow, four-petaled flowers in the summer months. The flowers are not particularly showy but are followed by seed capsules that can contain a prolific number of seeds, sometimes up to 1000 per capsule.

Willow primrose is valued for its ability to thrive in wet conditions, making it suitable for rain gardens and areas with poor drainage. It is also used for erosion control due to its fast growth rate and extensive root system. In cultivation, it prefers full sun to part shade and consistently moist to wet soil conditions. While it can be a beneficial plant in its native range, Ludwigia decurrens has become invasive in other parts of the world, such as Africa and Southeast Asia, where it can aggressively colonize rice paddies and wetlands, outcompeting native species and disrupting local ecosystems. Gardeners should be cautious about planting it in areas where it is not native to prevent potential invasiveness.CC BY-SA 4.0