Proserpinaca palustris var. crebra, commonly known as Mermaid Weed, is a semi-aquatic perennial herb native to freshwater habitats such as marshes, swamps, and the edges of ponds and streams in eastern North America. It typically grows up to 1 foot tall and can spread to form dense colonies. Mermaid Weed is characterized by its finely dissected, comb-like leaves that can vary in color from green to reddish, depending on light conditions. It produces small, inconspicuous green flowers during the summer months.

Mermaid Weed is appreciated for its feathery foliage, which adds texture and interest to water gardens and aquariums. It is relatively easy to maintain, requiring submerged conditions or saturated soil to thrive. In cultivation, it prefers full sun to part shade, and while it can adapt to a range of water conditions, it does best in slightly acidic to neutral pH levels. This plant is not commonly afflicted by diseases or pests, making it a hassle-free addition to aquatic settings. However, it is important to manage its growth to prevent it from overtaking smaller aquatic species.CC BY-SA 4.0