A prickly, tall plant, the Small teasel is closely related to the Common teasel, but has much smaller, more rounded flower heads. It prefers damp, open woodlands.

Selfheal is a low-growing, creeping plant that likes the short turf of grasslands, roadside verges or even lawns. Its clusters of violet flowers appear in summer.

A tall plant, purple-loosestrife can form dense stands of bright purple flower spikes in wet habitats like reedbeds, fens and marshes.

A small and delicate plant of chalk grasslands, Fairy flax can be seen in bloom from May to September - look out for its nodding, white flowers.

Greater celandine is a very common plant that spreads easily in the garden, on waste ground and in hedgerows. It is considered a weed, but the small, yellow flowers provide nectar for insects.

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.

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.

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.

Look for the pretty, azure-blue flowers of Wood forget-me-not along woodland rides and hedgerows, and in ancient and wet woodlands. Varieties of this flower for the garden are very popular.

Bittersweet is a nightshade, so is toxic; its bright red berries may be tempting, but can cause serious illness. Found in hedgerows and gardens, it has purple flowers with yellow stamens.