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.
A hive underground. Knowing what kind of bees or wasps you have in the ground may be the first step to the problem (wasp id). Very seldom do honeybees build nests in ground, unless in a rock like cave, against a bank or in a structure that's in the ground. Yellow jacket that look like bees are much more common types of ground bees. Bumblebees also can nest in low structures or in the ground. For basic identification visit the bee id guide.