Callitriche stagnalis, commonly known as Common Water-starwort, is a perennial aquatic herb native to a wide range of freshwater habitats in Europe and North Africa, including still or slow-moving waters such as ponds, lakes, ditches, and streams. It is often found in shallow, nutrient-rich waters and can tolerate brackish conditions, which is why it is sometimes present in salt marshes. This plant typically forms dense mats of vegetation that can cover the water’s surface.

Common Water-starwort is valued for its use in water gardens and ponds for its ability to oxygenate water and provide habitat for aquatic wildlife. It has a creeping growth habit with stems that can reach up to 70 cm long. The leaves are variable in shape, with submerged leaves being linear and thread-like, while floating leaves are broader. It does not produce showy flowers; instead, it has small, inconspicuous greenish flowers that appear from April to September. In cultivation, it requires an aquatic environment and can be grown in full sun to part shade. It is relatively low maintenance but can become invasive if not controlled, as it reproduces both vegetatively and through prolific seed production. It can be problematic if it escapes into natural waterways outside its native range, where it can outcompete native species and alter aquatic ecosystems.CC BY-SA 4.0