Plants for bumblebees

The tongue is the whole story

Bumblebee tongue lengths vary from a few millimetres to well over a centimetre, and the long-tongued species can drink from corollas no honey bee can enter. That opens a set of plants — red clover, foxglove, honeysuckle, comfrey, vetches, monarda — that are effectively bumblebee-only, and it is the reason a garden planted for honey bees and a garden planted for bumblebees are not the same garden.

An annual colony needs two things a perennial one does not

1. 1Early spring, for the founding queenEvery colony begins with one queen who has overwintered alone and must find food immediately on emerging, then feed herself and her first brood without workers. February and March forage — willow, lungwort, flowering currant, crocus, dandelion — is worth more to bumblebees than anything in June.
2. 2Late summer, for the new queensAt the end of the season the colony produces new queens who must build fat reserves for hibernation before they disappear. August and September forage — knapweed, scabious, michaelmas daisy, ivy, late thistles — decides how many survive to found colonies next year.

The middle of the season looks after itself in most gardens. The two ends are where planting decisions have measurable consequences, and both are the periods a garden designed for summer colour is empty.

Cold, wet, dark and large

• Bumblebees thermoregulate — they shiver to warm the flight muscles — so they fly at temperatures and in weather that ground honey bees, and in poorer light at the start and end of the day.
• They are heavy, so they work sturdy flowers and struggle with flimsy ones; a foxglove or a comfrey is built for a bumblebee's weight.
• They buzz-pollinate, so tomatoes, blueberries and other poricidal flowers are theirs rather than the hive's.
• They nest in existing cavities — old rodent burrows, tussocky grass, compost heaps, occasionally bird boxes — so rough grass left uncut matters as much as planting.