Bumbles on Blooms

In spring 2024 we called on gardeners to help us record bumblebees on flowers in gardens and parks

This project ran from 12 February to 31 May 2024. The project is now closed, and our scientists have started analysing the data gathered from over a thousand submissions to work out which flowers bumblebees prefer and how we can better provide for them. Discover the preliminary results below.

Project team

Gemma Golding, Senior Ecologist
Helen Bostock, Senior Wildlife Specialist
Ruth Chitty, Plant Pathologist
Laurel Emms, flower verifier

Partners

Bumblebee Conservation Trust

Dates

Surveys were open from 12 February 2024 to 31 May 2024

Results

Overview

  • Over a thousand records were submitted, which showed at least 10 bumblebee species and almost 350 different plants
  • Most popular plants were determined overall and by month – see breakdowns below
  • The top three most-recorded bumblebees that were identified to species level were early bumblebee, buff-tailed bumblebee and common carder bumblebee

  • Of all colours, white flowers received the most visits, closely followed by purple and pink
  • Records were evenly spread across urban and rural areas, but the highest number of sightings came from suburban locations, with 40% more records
  • At least 100 of the reported plants are not currently on the RHS Plants for Pollinators lists

The plants revealed

Chart toppers

These were the overall most popular flowers, with the most bumblebee sightings in total throughout the survey period. If you have a gap in your spring planting, why not include some of these popular bumblebee plants to provide a big boost to pollinators awakening from hibernation.
 

Monthly favourites

These were the five most popular flowers for bumblebee sightings in each month of the survey. You can ensure you’re providing a steady food supply for bumblebees during spring by choosing plants from each group on this list. For example, you could plant crocus, heather, comfrey, chives and allow dandelions to grow in your lawn.

February March April May
1 Crocus Crocus Dandelion Comfrey
2 Heather Heather Comfrey Chives
3 Winter honeysuckle Daffodil Rosemary Aquilegia
4 Mahonia Grape hyacinth Lungwort Perennial cornflower
5 Hellebore Flowering currant Green alkanet Foxglove

“It’s great to see a mix of cultivated plants and wildflowers among the favourites. Autumn is a great time to plant these, especially the spring bulbs such as crocus, daffodil & grape hyacinth.”

Helen Bostock, Senior Wildlife Expert

New potential

At least 100 of the reported plants are not currently on the RHS Plants for Pollinators lists, suggesting bumblebees may rely on many more plants than previously thought, and showcasing the adaptability of these pollinators in sourcing nectar and pollen during spring.

The below plants aren’t currently on our RHS Plants for Pollinators lists, but showed promise as key bumblebee forage plants in the survey. Some of these plants may now be considered for inclusion on the lists.
 

So what should I do?

Gardeners looking to attract bumblebees can do so by planting a mix of early-flowering species. Crocuses and chives can thrive in pots or alongside vegetable beds, while comfrey and dandelions work well in wildflower gardens and informal lawns. Meanwhile, heather is a great low-growing evergreen shrub for providing colourful ground cover in sunny spots.

Early autumn is the perfect time to plant shrubs, perennials and spring bulbs, while the ground is moist and temperatures still mild. For best results, plant in groups in sunny, sheltered parts of the garden to create bee-friendly patches, ensuring there are blooms available throughout the season to support the bumblebees’ ongoing foraging needs.

What difference has this project made?

Information gathered by the Bumbles on Blooms project has increased our understanding of which garden plants are most visited by bumblebees in spring, helping us improve our RHS Plants for Pollinator lists and give the best advice to gardeners planting for bumblebees.

RHS Senior Wildlife Specialist Helen Bostock says: “Bumblebees are a vital part of our ecosystem. Faced with large-scale changes to the countryside, flowers in gardens and parks are an increasingly important source of pollen and nectar for these precious pollinators. The long, wet spring this year made it especially challenging for bumblebees to establish their colonies, so this project has been very timely.

“The public’s observations have highlighted the importance of a diverse range of plants in supporting bumblebee populations throughout spring. This data will help us refine our recommendations and encourage more gardeners to plant for pollinators, especially as autumn offers the perfect window for planting both spring bulbs and perennials.”

Bumblebee on green alkanet, one of the most reported plants for April.

Photo: Olivia Drake

Common carder bumblebee. Photo: Helen Bostock

Dr Richard Comont, Science Manager at Bumblebee Conservation Trust, added: “Spring is a key time for bumblebees – it’s when queens are under maximum stress, foraging on their own as they establish their nests.  It’s fantastic to see so many people sent in sightings to the survey, and the information it has provided will be a huge boost to the survival of these iconic species.”

The Bumbles on Blooms project has been recognised as a Bees Needs Champion, one of 45 projects awarded by Defra in recognition of their efforts in championing pollinators in 2024.

Project background

Why did we need your help in monitoring bumblebees on flowers?

Bumblebees are a key group of wild pollinators, helping to pollinate our garden plants as well as crops such as tomatoes and fruit trees. Like many pollinating insects, bumblebees face the challenges of habitat loss and climate change.

The availability of flowers in spring is especially critical for helping them to establish successful colonies at the start of the season. Bumblebees mostly overwinter in the UK as queens, which emerge from sheltered places such as underground burrows as the weather warms. Flowers are needed to provide nectar; a sugary fuel for powering bees’ flight. Meanwhile, the protein-rich pollen from flowers is fed to the developing larvae of the worker bumblebees.

Bumblebee on comfrey. Photo: Helen Bostock

Bumblebee on hellebore. Photo: Helen Bostock

What did we do?

So we know that spring flowers are important, but which flowers do bumblebees use?

To help us find the answer, we invited gardeners across the UK to become community scientists and help spot bumblebees on flowers this spring.

We know that plants in gardens and parks can complement flowers from the wider countryside for bees, often offering a longer season and wider range than wild flowers alone.

To help us capture this information, we used a popular wildlife recording tool called iNaturalist. This can be downloaded as an app onto a smartphone and used to capture records of plants and animals when you are out in your garden or local park. Records were then be submitted to our ‘Bumbles on Blooms’ project within iNaturalist.

How to recognise a bumblebee

Bumblebees are one of the more familiar bees we see in gardens. They vary in size from a large pea to a large olive. Here are some distinctive features to look out for.

  • Rounded body shape – they often look ‘plump’ compared to other types of bee
  • Very hairy all over the body – other bees can be smooth or hairy but not usually as hairy as bumblebees
  • On the female bumblebees (queens and workers) you might see pollen baskets on their hind legs – these can be full of pollen, balls of yellow, orange or pink depending on the flowers they’ve been visiting

  • Hair colour varies depending on species – some are black with white or yellow stripes, some have 3 colour bands in white, black and ginger, while some are ginger all over
  • Eyes oval-shaped on the sides of their heads – this helps distinguish them from flies which mimic bees as flies have very large round eyes which cover much of their head
  • A ‘bumbling’ flight – due to their large body size compared to their wings, bumblebees can often fly in a rather haphazard manner, from which we get the expression ‘to bumble around’!

Further information

Below are some great resources put together by Bumblebee Conservation Trust.
 
  • Watch this 5-minute video on identifying the most common bumblebees in the UK 
  • Check these top tips for photographing bumblebees
You can track your own and other records submitted to our project on the iNaturalistUK page.

White-tailed bumblebee queen on strawberry tree. Photo: Helen Bostock

Useful links

Learn more about bees in your garden

How to help our declining bees and other pollinators

New research from the Universities of Exeter and Oxford highlighting the importance of early flowers to bumblebees

If you’ve enjoyed being part of our Bumbles on Blooms project and would like to record bumblebees more regularly, consider taking part in Bumblebee Conservation Trust’s BeeWalk scheme.

More on planting for bees and other pollinators:

More on Science with the RHS

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.