Ground-elder was likely introduced into the UK by the Romans and has since become naturalised. A medium-sized umbellifer, it is an invasive weed of shady places, gardens and roadsides.

Despite its name, Ground-ivy is actually a member of the dead-nettle family. It is a clump-forming, aromatic plant that likes woodlands, hedgerows and damp places.

Red squirrels are native to the UK but are a lot rarer than their grey cousins. They live in a few special places across the UK thanks to reintroduction projects.

The delicate, tube-like, violet-blue flowers of Skullcap bloom from June to September in damp places, such as marshes, fens, riverbanks and pond margins.

A tall and hairy plant, Great willowherb displays pretty pink-and-cream flowers. It can be found in damp places, such as wet grasslands, ditches and riversides.

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.

A low-growing plant of sand dunes, heaths and grassy places, Common centaury is in bloom over summer. Look for clusters of pretty, pink, five-petalled flowers.

Although introduced by humans, the fallow deer has been here so long that it is considered naturalised. Look out for groups of white-spotted deer in woodland glades.

A notoriously poisonous plant, hemlock produces umbrella-like clusters of white flowers in summer. It can be found in damp places, such as ditches, riverbanks and waste ground.