Dog Rose (Rosa canina) – great for short-tongued bumblebees
Dear Readers, as I was leafing through my Bumblebee Conservation Trust newsletter this week, I read that a bumblebee with a full stomach is still only 40 minutes away from starvation. Yikes! No wonder these Einsteins of the insect world have learned a number of techniques to maximise their nectar uptake. But first, let’s have a quick think about the differences between different species of bumblebee.
Plant preference is all down to the length of a bumblebee’s tongue. There are short-tongued species, whose tongues are only 6- 8.5 mm long, and these bees love open, easily accessible flowers like the dog rose above. Species include our old favourite the buff-tailed bumblebee (Bombus terrestris) and the newcomer the tree bumblebee (Bombus hypnorum)
Buff-tailed queen bumblebee on winter flowering honeysuckle, with teeny tiny tongue…
Other species, including my favourite the common carder bumblebee, have much longer tongues (up to 20 mm) and they can access nectar in plants such as foxglove, comfrey and thistles.
Common Carder Bumblebee on Cirsium atropurpureum
But I’m sure you’ll have seen bumblebees on plants that they’re not ‘meant’ to be on – I’m sure I’ve seen buff-tails fighting their way into foxgloves, for example. The point is that bees waste energy trying to access nectar in plants that they aren’t ‘designed’ for, and so some of them cheat, by chewing a little hole in the base of a deep-throated flower and then ‘nicking’ the nectar without a fight. Furthermore, Dave Goulson (who is undoubtedly one of the world’s most knowledgeable bumblebee experts) has found that bumblebees can learn how to nectar rob by observing other bees doing it. Amazing!
So, here is the BCT’s list of top plants for bumblebees with different tongue lengths:
Short-tongued bees:
Bramble
Goat Willow
Borage
Dog Rose
Borage (Borago officinalis)
Long-tongued bumblebees
Comfrey
Foxglove
Red clover
Spear Thistle
White comfrey
Foxglove (Digitalis purpurea)
And at this time of year, let’s not forget Mahonia – not native, but a very important source of nectar for queen bumblebees emerging for a quick nibble on mild days in winter. There was a huge bee the size of the first joint of my thumb on the mahonia in the garden this week, and I was so glad it was in flower.
Mahonia flowers
So important to have a wide variety of plants with an emphasis on natives – for all kinds of insects. And as you say, the non-natives fill seasonal gaps nicely. I’ve managed – at last – to have something in flower every month of the year in my scruffy wildlife garden. Winter Jasmine, Mahonia, and Clematis cirrhosa Jingle Bells fill in ‘November to spring bulbs’ really nicely, and in a mild year, my Geranium macrorrhizum are almost constantly in flower, though the number of blooms can get a bit sparse in some months, and they don’t much like temperatures below zero.
Nice choices, Jay!