...queen] or is the best you can do.... ...just to create likely habitat for them to colonise, and plant the sort of plants they like to visit.

Bumble bees are native american bees and do not have large colonies. They often live in small holes they excavate in rock gardens. That is where mine reside.
Plant it and they will come. Depending on where you live.

yes call your department of agriculture and they can instruct you on how to do exactly that. Good luck and remember you will have to organically keep your garden.