Mowing the lawn just once a month – and leaving some areas to grow long – provides a huge boost to flowers, bees and other wildlife, experts have said.

The “Mohican” haircut approach to mowing is being recommended by wildlife charity Plantlife, after a citizen survey of lawns revealed they can support 200 different flowers and generate huge amounts of nectar for wildlife.

While people are spending more time tending their gardens during lockdown, Plantlife is urging people to leave the lawnmower in the shed during May and then take part in the survey to reveal the nectar-rich flowers in their lawns.

It comes after the first “every flower counts” survey in 2019 revealed – to the surprise of the experts – that some mowing can help lawns be wildlife-friendly habitats.

Plantlife, which asked people to record the flowers in a random square metre patch of lawn, estimates the nearly 2,000 lawns in the survey were producing 50lb (23kg) of nectar sugar a day, enough to support 2.1 million honeybees.

On average most lawns could support 400 bees a day, but “superlawns” with lots of flowers can support as many as 4,000.

Plantlife’s Dr Trevor Dines said: “In the past we’ve been imagining that leaving your grass completely unmown and letting the flowers grow throughout the whole of the season is the best thing you can do for pollinators to get the maximum number of flowers in an area of grass.

“But what we’ve discovered with the survey – and this was a real shock to us when the results came in – is we’ve almost got two distinctly different types of habitat in our gardens.

“One where plants are adapted to long grass that’s allowed to grow throughout the year, but we’ve got this little group of plants that are highly adapted to growing in short grass.”

These flowers include daisies, selfheal, dandelions and white clover, which produce lots of nectar.

Even if you have a pocket handkerchief lawn, you can make a really valuable contribution to our pollinators

They grow below the blades of the mower and if their flowers are cut off they produce more – as long as they are not cut too often, with monthly mowing having the greatest benefit.

The survey also revealed a huge range of flowers growing in longer grass, including oxeye daisy, field scabious, knapweed and even orchids.

Dr Dines said: “We’ve got a small range of flowers producing a lot of nectar on short grass, but a much wider range of flowers producing nectar in long grass.

“In any garden, if you adopt this Mohican style of mowing, having those two together maximises the amount of nectar, but also the amount of different nectar being produced over time because different insects need different flowers.

“You get that wide range of flowers in the long bit of the Mohican and a narrow range of flowers but producing more nectar in the short back-and-sides.”

It also means householders can have tidier areas of lawn and defined patches of long grass that do not look neglected.

While the average lawn size in the survey was around the size of a tennis court, small urban gardens can also play their part, Dr Dines said.

“Even if you have a pocket handkerchief lawn, you can make a really valuable contribution to our pollinators,” he said.

– To find out more about “No Mow May” and take part in 2020’s every flower counts survey from May 23-31, people can visit www.plantlife.org.uk/everyflowercounts/