As its name suggests, giant hogweed it a large umbellifer with distinctively ridged, hollow stems. An introduced species, it is an invasive weed of riverbanks, where it prevents native species…

The Holm oak is an introduced species that has been widely planted near the coast and in parkland. It is self-seeding in the south of the UK. Its young leaves are spiny like Holly leaves, and it…

A tall, broad tree of woodlands, roadsides and parks, the introduced horse chestnut is familiar to many of us the 'conker' producing tree - its shiny, brown seeds appearing in their…

The Sitka spruce was introduced into the UK from North America in the 19th century. It has been widely planted as a forestry tree; look for classic needle-like leaves and pale brown, domed cones…

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…

Introduced into the UK in the 19th century, the diminutive little owl can now be seen along hedgerows, on farmland and in parkland across England and Wales. It often perches on a pole or rock,…

A handsome gamebird, the pheasant is an introduced species that has settled here with little problem. It can be spotted in its farmland and woodland habitats, although you'll probably hear…