Garlic is a pungently odoriferous member of the allium family (like onions and leeks). Garlic is generally used as a spice or a seasoning rather than as a vegetable due to its extremely strong flavour. Garlic grows in large papery heads. A novice mistake is to massively overgarlic things by following instructions incorrectly. Remember that the large bulb of garlic you buy is NOT one 'clove'. The whole garlic is called a 'head' or 'knob'.
Bumblebees do not damage brickwork or wood. Some of the bumblebees which make smaller nests, Bombus pratorum and B. hortorum do sometimes chose strange places to nest. Their nests are small and in the case of B. pratorum are usually very short lived.
Bumblebees do not swarm. Some species like Tree bumblebees (Bombus hypnorum) have distinct mating behaviour in which male bumblebees from all around will seek out a nest and fly around outside. They dance around in the hope that they will get a chance to mate with a new queen as she leaves the nest.