Bumblebee queens and their foraging plants
Soon last years ‘new bumblebee queens’ will be emerging from hibernation, feeding up on pollen during the day and hiding from overnight frosts. Then healthy queens (as opposed to nematode infected ones) will shortly be looking for nesting sites. Single queens establish one nest, providing certain requirements are met.
Nest searching behaviour

Watch for low level flight zig-zaging, along field boundaries, rough grasslands, garden fences, stone walls, under hedges, banks, hollows, compost heaps and around sheds. You will hear a low buzz followed by a ‘buzz ump!’ as she lands to recce a potential nest site. e.g. small mammal nests. NB. She has no pollen inside her pollen baskets.

 

Notice pollen in her pollen baskets. She has a nest

Forage is critical
Access to nearby spring flowers is critical for the successful establishment of her nest. Quite simply no flowers for queens = no food = no bumblebees. Scarcity of spring forage has a detrimental effect on the survival of overwintered queens and their nests. They need to obtain adequate supplies of nectar, to fuel flight and generate heat, with pollen (protein) for her offspring. I have often watched queens leave their nest and forage on flowers in my garden.

Bumblebee queens need early flowers nearby

What does she do?
Inside her chosen site, she creates a brood chamber, a pollen mound, (brood clump), on which she lays eggs. She makes a wax pot to store nectar, (honey pot) to feed from during inclement weather and during the night. She will sit brooding her eggs, keeping them warm, by muscular activity, similar to shivering! When hatched, she supplies larvae with pollen/nectar in a manner that depends on the species. As the first brood grow, she enlarges the brood cells and lays more eggs. Soon she will remain in the nest, egg laying and undertaking other nest duties.

Wax honey or nectar pot used to top up in bad weather

Danger when venturing out
Keeping her brood warm requires energy. Besides during the nights and during poor weather, e.g. fog or heavy rain, she may have to stay inside the nest. She is then dependent upon her honey pot reserves. If it is empty she will have to forage and leave her nest. The longer she is away from her comfy brood chamber, with its bounty of pollen, nectar, eggs, larvae or pupa, the more likelihood it may be raided by predators or destroyed by mice. Whilst outside foraging, the chances of her being injured, killed or eaten, are increased. The nearer her forage flowers, the better chance her nest will survive. We need to plant the right flowers though!

They may look lovely to us but double flowers are useless for bees!

What to plant for bumblebee queens

They do not care whether it is a tree, shrub or a flower, native plant or non native. It’s the pollen and nectar they need and if a plant provides it, that’s all that matters to them! Like us, they need a variety of food to keep healthy. Our bumblebee queens need them and they need them to be neonicotinoid free

“All my articles and videos, available free, are funded by my  teaching and sales of award winning bumblebee nest boxessolitary bee boxes,  and wormeries. Please help by spreading the word and forwarding this link to your friends and colleagues. https://nurturing-nature.co.uk  Thank you” George Pilkington

Please consider planting these plants to cater for our different bees species, or leaving them to flower in the case of dandelions.

Dandelions

Dandelions are used by bumblebees, honeybees, solitary bees, hoverflies, butterflies, moths and caterpillars. Goldfinches eat the seeds! Do not use weed killer! Let them flower and later de-head them.

Alkanet
Aubrietia
Berberis e.g. Darwinii
Blackthorn
Comfrey
Crocus (single)
Dandelion
English Blue Bell
Flowering current
Fruit trees/shrubs 
Grape hyacinth
Hazel
Heathers (Winter/early spring spp.)
Lesser celandine
Lungworts (Hairy footed flower bee likes as well!)
Wall flower e.g. Bowles’s Mauve
White/red dead nettle
Wild primrose (esp. B. hortorum)
Wild daffodils
Willow spp. (e.g. Kilmarnock Willow for gardens)
If anyone would like add to my list please contact me. Thanks.

Bumblebee queen on willow

Soil Association organic herbaceous perennials and alpines try Caves Folly
For peat and pesticide free plants try rosybee 
Further reading
“Plants for bees: A guide to the plants that benefit the bees of the British Isles” by W.D.J. Kirk and F.N. Howes.– Excellent updated book, covers wild and honey bees, with lavish photographs, written by experts.
Interested in citizen science and pollinators? The BuzzClub
For an interesting, light hearted read try ‘A Sting in the Tale’, by Dave Goulson