Hedge mustard is a tall plant with small, yellow flowers atop tough stems. It likes disturbed ground and grows in hedgerows and roadside verges, and on waste ground.

Arrowhead is an aquatic plant of shallow water and slow-moving waterways. In bloom over summer, it displays small, white flowers, but it is the arrow-shaped leaves that are most distinctive.

Considered to be one of the prettiest gentians, the Chiltern gentian is a rare plant in the UK. It likes chalk grasslands, its purple, trumpet-shaped flowers blooming from August.

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.

Creeping jenny is a low-growing plant of wet grasslands, riverbanks, ponds and wet woods. It has cup-like, yellow flowers and is a popular choice for garden ponds.

The early gentian is a rare plant that is only found in the UK. It likes sunny, lowland chalk grasslands, its purple, trumpet-shaped flowers blooming in May and June.

With club-shaped leaflets on its fronds, wall-rue is easy to spot as it grows out of crevices in walls. Plant it in your garden rockery to provide cover for insects.