No Mow May

The charity Plantlife is asking people to consider letting their lawns grow during May to encourage wildflowers and provide nectar for bees, butterflies and other pollinators. They call it ‘No Mow May’ They are also asking people to take part in their ‘Every Flower Counts’ survey at the end of the month, by counting the flowers in one square meter of the lawn and submitting the results.

Plantlife points out that, plants need pollinators and pollinators need plants, but both are in decline. However, the UK’s millions of garden lawns have a part to play in addressing this.

2021 is the third year that Plantlife is running this initiative. Already is has shown that garden lawns support a huge diversity of wildflowers and that making simple changes in mowing, to allow flowers to develop, can dramatically increase the amount of nectar available to pollinators.

The first survey in 2019 found over 200 species of plant flowering on lawns. It also showed that the greatest production of flowers and nectar sugar is achieved if lawns are mown only once every four weeks, allowing a profusion of short-stemmed flowers to develop. Unmown lawns left for longer produce a greater variety of wildflowers, increasing the range of nectar sources for different pollinators and extending nectar availability into late summer. Plantlife is using these annual surveys to help develop new guidelines on how to manage lawns for wildlife and will be announcing the findings of the 2020 survey soon. They recommend, among other things, keeping two lengths of grass – leaving some patches unmown to let taller flowers come into bloom and for the rest mowing once every month to a height of 1 or 2 inches.


Taking part in 2021

Details can be found at www.plantlife.org.uk and to take part you are asked to do three things:

1. Leave the mower in the shed for No Mow May and let the flowers grow.

2. From 23rd May to 31st May take part in the ‘Every Flower Counts’ survey by counting the number of flowers in a random square metre of your lawn. Instructions are provided.

3. Enter the count on their website. It will generate a Nectar Score, showing how much nectar is being produced by the flowers on your lawn and how many bees that could support.


Iain and Eliza Naismith

  • On a single day in summer, one acre of wildflower meadow can contain 3 million flowers, producing 1 kg of nectar sugar. That’s enough to support nearly 96,000 honey bees per day.

  • But since the 1930s, we have lost nearly 7.5 million acres of flower-rich meadows and pastures. Just 1% of our countryside now provides this floral feast for pollinators.

  • Against this loss, habitats such as lawns have become increasingly important. With 15 million gardens in Britain, our lawns have the potential to become major sources of nectar.

  • But no one has ever quantified this resource before. This is what Every Flower Counts aims to do: work out how many flowers are on our lawns, how much nectar they’re producing and how many bees they can support through the calculation of our annual National Nectar Score.

  • Every Flower Counts will then allow us to monitor trends over time. Can we manage our lawns differently to increase the National Nectar Score? Will climate change have an impact on flowering and nectar production? What are the most abundant flowers and what can we do to encourage them?

By taking part in Every Flower Counts, you’ll help us answer these questions and get your very own Personal Nectar Score to show how many bees your lawn can support.

Dr Trevor Dines, who created the survey, explains all about No Mow May and Every Flower Counts in this webinar.


In 2019 Every Flower Counts participants counted the flowers in nearly 5,000 one-metre quadrats in lawns all the way from the Channel Islands to Shetland. The results are fascinating and surprising.

495,676 individual flowers were counted

203 different species were found, including orchids and other rarities such as meadow saxifrage, knotted clover and eyebright

The top 7 lawn flowers were (total counted in all quadrats):



But the top 7 nectar producers were (average μg nectar sugar/quadrat/day):



The first-ever National Nectar Score shows that:

  • The average lawn produced 12 grams of nectar sugar per day, enough to support 1,088 honeybees.

  • When combined, all the lawns in the survey produced a whopping 23 kg of nectar sugar per day. That’s enough to support 2.1 million honeybees per day.

Lawns showed a big variation in the average nectar they produced:



Long-grass: Leave some patches completely unmown to let taller flowers bloom. Cut these areas at the end of summer or early autumn.



In a big surprise, flower and nectar sugar production was highest on lawns cut once every four weeks. This gives ‘short-grass’ plants like daisies, selfheal and white clover a chance to flower in profusion, boosting nectar production tenfold.

But areas of longer unmown grass were more diverse in their flowers, with plants like oxeye daisy, field scabious and knapweed increasing the range of nectar sources for different pollinators and extending nectar availability into late summer.

These findings pave the way for new guidelines on how to manage our lawns. Rather like a Mohican hair-cut, we suggest keeping two different lengths of grass:



Short-grass: For the rest of the lawn, keep the grass shorter by mowing once every month – 4 or 5 times a year – to a height of 1 or 2 inches (2.5 to 5 cm). Some flowers will be cut off when you mow but they’ll come back quickly; you can even rotate patches around your garden so there are always some areas in flower.


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