The tree bumblebee was first recorded in Britain in 2001, close to the Hampshire–Wiltshire border, and has since spread steadily north. Here in Hampshire, the tree bumblebee is now well established and can be spotted in gardens, parks and woodland‑edge habitats.

Unlike many bumblebee species that nest underground, the tree bumblebee is highly adaptable. It prefers to nest above ground in cavities such as bird boxes, old birds’ nests and roof spaces. 

The queens are among the earliest bumblebees to emerge in spring. After feeding on early flowers to rebuild their energy reserves, they search for a suitable nest site and lay their first batch of eggs. Around six weeks later, the first worker bees emerge to take over foraging and nest‑building duties, allowing the queen to remain inside the nest laying more eggs.

The tree bumblebee is one of the ‘Big Eight’ common and widespread bumblebees in the UK. All three castes (queen, worker and male) share the same distinctive colour pattern. In males, the ginger‑brown hair can sometimes extend onto the front of the abdomen. Some individuals appear much darker, with little ginger hair on the thorax; this variation, known as melanism, occurs in many bumblebee species but is particularly common in tree bumblebees.

The bees have a short tongue and visit a wide range of flowers, especially brambles, raspberries and cotoneaster, making it an important pollinator for gardeners and growers alike. Gardens with woodland, trees, shrubs and flowering plants, provide ideal conditions for this species to thrive. 

During late spring and early summer, ‘swarming’ takes place around nest entrances. While this can look alarming, it is harmless behaviour: these are males waiting to mate with newly emerging queens, and male bumblebees do not sting. Males are typically seen in May and June, and in warm years the species may produce a second generation, meaning adults can still be spotted well into autumn.