No fuchsia: RHS call to ditch exotic plants

GARDENERS should drop exotic plants for British ones to help wildlife, the Royal Horticultural Society has advised, following a fiveyear experiment.

In 2012, experts at the RHS filled 36 plots of land in Wisley, Surrey, with 14 different species from either Britain, the northern hemisphere, or the southern hemisphere. The plots were then tended like a normal garden for 48 months to see which insects moved in.

It is the first research project to test whether the geographical origin of garden plants affect the amount and different types of insects and spiders they support.

The experiment showed that insects were three times as likely to choose plots with native British plants than exotic species. Out of the 22,000 bugs collected from the patches, 56 per cent of all invertebrates were found in the native gardens compared with 26 per cent in the nearnative plots, and just 19 per cent choosing the more exotic varieties.

Detritivores, such as woodlice and worms which provide a crucial leaf-eating service which fertilises the soil, were 24 per cent higher on the native plots than the exotic and 36 per cent higher than on near-native plots.

Andrew Salisbury, RHS principal entomologist, said: “In order to help create a positive environment for these valuable invertebrates to thrive, gardeners should plant plenty of plants from the UK and relax, refrain from spraying plants at the first sign of pest attack, and reduce trimming and allow some plant debris to accumulate in order to support the garden’s food chain.”

The RHS suggests attractive native plants that gardeners can add to borders to boost wildlife include foxgloves, purple loosestrife, common honeysuckle and heather. In contrast, avoiding thyme, dahlia and fuchsia could help native insects. The study was published in the journal Biodiversity and Conservation.