As its name suggests, the Marsh violet likes damp spots, such as marshes, bogs and wet woods. It is a low-growing plant with kidney-shaped leaves and pale lilac flowers.

The Marsh helleborine is a beautiful orchid of fens, wet grassland and dune slacks. Growing in profusion in places, look for reddish stems and white-and-pink flowers.

Europe's largest frog is not naturally found in the UK, but was introduced to Kent and has spread throughout the southeast.

The bright blue, trumpet-shaped flowers of the marsh gentian contrast deeply with the pinks and purples of the wet heaths it inhabits. The New Forest holds a large population of this late-…