Marginal pond plant
Marsh pennywort
Hydrocotyle vulgaris
A low-growing, mat-forming marginal perennial for pond edges and bog gardens, valued for habitat and groundcover. Plant shallowly at the water’s edge and cut back to control spread.
PLANT PROFILE
About Marsh pennywort
Marsh pennywort (Hydrocotyle vulgaris) is a mat-forming, creeping marginal perennial recommended for pond margins and bog gardens. It forms a carpet of rounded leaves on short petioles and can be grown positioned at the water’s edge or shallowly submerged. Freshwater Habitats Trust advises planting in 2–10 cm of water at the margin, while RHS describes it as growing shallowly submerged in water up to 5 cm deep. RHS gives a maximum height of about 10 cm and a spread typically up to 10–50 cm.
This species is treated in the supplied sources as a native UK wetland plant and is included in garden-pond planting lists as suitable for wildlife ponds. It provides marginal and shallow-submerged habitat and shelter for amphibians and invertebrates rather than functioning as a significant nectar source or as a named oxygenator. RHS notes the foliage is deciduous (dies back over winter) and rates the plant as hardy (H5). Propagation is by division, and routine cutting back is recommended to keep the mat in check.
When sourcing and managing pennywort, the supplied guidance strongly advises confirming identity: the invasive floating pennywort (Hydrocotyle ranunculoides) is regulated and can be confused with native pennyworts. GOV.UK invasive-species guidance and Freshwater Habitats Trust materials emphasise not releasing pond plants or pond contents into wild waterbodies. RHS notes the species is generally pest-free but can be susceptible to mint rust. Use planting at the shallow margin of a pond or in boggy soil, monitor spread and dispose of trimmings responsibly to avoid accidental wild introductions.
POND SUITABILITY