Epilobium leptophyllum, commonly known as bog willowherb or linear-leaved willowherb, is a perennial herb native to wet meadows, marshes, and the edges of ponds and streams in eastern and northern North America. It typically grows up to 1 meter tall and can spread through its tiny stolons, which allow for vegetative propagation. The leaves of bog willowherb are linear, reaching up to 3 inches in length, and the plant produces an inflorescence in the form of a raceme composed of small, delicate flowers with white to pink petals that bloom in the summer months. The fruit is a distinctive hairy, elongated capsule that releases seeds upon maturity.

Bog willowherb is valued for its ability to thrive in wet conditions and is often used in rain gardens or as a part of naturalized wetland plantings. It is also appreciated for its low maintenance requirements and its adaptability to a range of moist soil types. In cultivation, it prefers full sun to part shade and consistently moist to wet soils. While not commonly afflicted by diseases, it can sometimes be susceptible to rust. This plant is not typically associated with aggressive roots, making it a safe choice for gardeners looking to add native wetland species to their landscapes. CC BY-SA 4.0