How to help hibernating bumblebees

By Annie Ives, Bumblebee Conservation Trust Information Officer

Bumblebees do not make honey, so unlike honeybees (which live inside their hive all winter feeding on the honey that they produce throughout the summer), bumblebee nests have a short, annual lifecycle, completely relying on flowers for all their food.

At the end of the summer (and sometimes half-way through, depending on the species!) – when their favourite flowers have gone to seed and died off – big, bright bumblebee queens emerge from their nests and begin to look for somewhere safe and cosy to hibernate.

Queen bumblebees can live up to 12 months but spend up to half of their lives in a dormant state. When the new queens emerge from the nest, the rest of the bumblebees, which only live for a few weeks, start to die off naturally.

Queen bumblebees mate before going into hibernation, so by the time they emerge in spring or summer the following year, they are already carrying everything they need to start a brand new nest and create the next generation of bumblebees.

How to provide potential hibernation spots

Queen bumblebees will hibernate in a variety of places, from well-drained, soft soil, to leaf litter, hollow trees or inside tree bark. They often choose spaces that are north-facing, so they get less winter sun and the ground doesn’t heat up and wake them up early.

The best hibernation spots will also be on a slope or raised area, making them less likely to flood. Queen bumblebees use their legs to dig bumblebee-sized holes into the soil or other substrate, and can excavate to a depth of more than 10cm!

In your outdoor space, you can create safe hibernation spots for bumblebee queens by:

• making log piles (and leaving them alone)
• leaving dedicated areas of leaf litter
• building an open compost heap or raised bed
• creating a ‘bee bank’ – this is a shallow sloping bank of bare, sandy soil. (If you are lucky you could have hibernating bumblebees on the north side over winter, and solitary bees nesting on the south side in the summer!)
• leaving ‘untidy’ or wild areas with longer grass, moss, and cover.

How to avoid disturbing hibernating bumblebees

You might come across a hibernating queen when carrying out winter or spring jobs in your garden, such as repotting plants, turning compost or planting bulbs. If you accidentally disturb a hibernating bumblebee, don’t panic! Gently cover her back over with the same material that she had dug into and leave her be.

If she is buzzing around and won’t go back into hibernation, place her somewhere sheltered (for example, under some leaf litter). Bumblebees need to be outside to complete their lifecycles, so never take them indoors.

Helping winter-active bumblebees

In the UK, ‘winter active bumblebees’ are becoming more and more common especially in the south of England – possibly as a result of our changing climate. Instead of going into hibernation, these queens set up their nests in autumn and you could find their daughters visiting your flowers all through the winter!

Growing flowers such as winter heathers and winter honeysuckle will help keep them well-fed throughout the colder months. Winter-flowering mahonias are also great for bumblebees, but do have the potential to spread outside gardens so should be pruned soon after flowering.

Discover more from our Bee the change resources.