Guide

Happening unseenInsects

Bumblebee queens dormant underground in winter

December to March

After the first hard frost, every bumblebee colony from summer is gone except the young queens that mated in autumn and are now dormant in the ground. Each one is waiting alone under leaf litter or loose soil to start a new colony in spring.

Why this time of year

The summer colonies have died out, and the only bumblebees left alive are sleeping queens, each one holding next year's whole population.

How to notice it

  1. Look at a leaf-covered garden bed or the base of a tree or shrub and picture a sleeping queen somewhere beneath it, since she is not visible and should not be looked for.
  2. Leave leaf litter where it has fallen around trees, shrubs, and perennials, and do not rake it away or till the soil.
  3. Hold off on spring cleanup until mid-April or until daytime temperatures are consistently 50 F, which is warm enough for most native insects to have come out.
  4. Count how many bumblebees you saw last summer, then remember that one queen starts each new colony.

Try this with kids: Stand beside a pile of leaves and whisper good night to the queen bee you cannot see, then promise to leave the leaves alone.

Sources

  • massaudubon.orgMass Audubon (2022-10-01): young queens mate then survive winter in the ground under leftover leaf litter until spring; leave deep leaf litter around trees, shrubs and perennials and hold off cleanup until mid-April or consistent 50 F days. Quote: 'the young queens mate and then survive the winter in the ground under leftover leaf litter until the warmer days of spring' Refute pass 2026-10-30 also read: 'Common Eastern Bumble Bee colonies ... work and produce young queens well into autumn. These queens fly off to mate while the colony continues to work until the first hard frost, when they die.' and 'hold off any cleaning efforts until mid-April or when daytime temperatures are consistently 50 F. This is warm enough for most of our native insects to have emerged.'
  • pollinators.wisc.eduUW-Madison pollinator program: colonies produce new queens and males before workers and old queens die in fall; males die, young queens burrow underground and stay dormant until spring; leave leaf litter in garden beds. Quote: 'the young queens burrow underground or in other safe places where they stay dormant until spring'
  • wisconsinbumblebees.entomology.wisc.eduUW-Madison Entomology: after reproductives are produced the workers and founding queen die, leaving only newly mated queens; mated queens dig into loose soil and thatch; dormancy 6-9 months; overwintered queens emerge mid-late April to early May (Wisconsin timing). Quote: 'the workers and founding queen will all die out naturally, leaving only the newly mated gynes'
  • extension.colostate.eduColorado State Extension: only mated queens survive winter, hibernating in leaf litter, a wood pile, or underground; colony ends as temperatures drop; leaf litter disturbance before emergence can harm them. Quote: 'Newly mated queens are the only bumble bee survivors during the winter.'

Checked against these sources on October 30, 2026.

In the guide for December, January, February, March

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