Gardeners are being encouraged to let grass and wildflowers bloom for ‘No-Mow May’. The annual campaign acts as a reminder of all the ways we can support insects, tackle pollution and slash emissions in our own backyards. Putting away your lawn mower and allowing native plants to flourish is one of the best ways to help pollinators do their essential work. Letting your lawn grow can also increase butterfly numbers by over 90 per cent, a recent study has shown. But it may require you to rethink your prejudices: even plants traditionally considered as weeds, such as ragwort, hawthorn and ladytho…