An uncommon hedgerow and woodland tree of central and eastern England, purging buckthorn displays yellow-green flowers in spring, and poisonous, black berries in autumn.

An easily overlooked orchid, the Common twayblade is yellow-green and less showy than other UK orchids. Look for it in woodlands and grasslands on chalky soils, in particular.

As its name suggests, Sea spurge is found at the coast. It is an attractive plant that displays cup-shaped, greeny-yellow flowers and fleshy, grey-green leaves.

Our largest shieldbug, the red-and-green hawthorn shieldbug can be seen in gardens, parks and woodlands, feeding on hawthorn, rowan and whitebeam. The adults hibernate over winter.

An attractive, green-and-yellow bird, the siskin regularly visits birdtables and feeders in gardens. Look for the bright yellow barring on its black wings, and the black crown of the males.

In spring and summer, look out for 'cuckoo-spit' - the frothy mass of bubbles that appears on plant stems everywhere. This is actually the protective covering for the nymphs of the tiny…