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.

The turnstone can be spotted fluttering around large stones on rocky and gravelly shores, flipping them over to look for prey. It can even lift rocks as big as its own body! Although a migrant to…

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.

Introduced from Japan in the 19th century, Japanese knotweed is now an invasive non-native plant of many riverbanks, waste grounds and roadside verges, where it prevents native species from…