It sounds as if the ground bees that you call bumble bees are in fact bumble
bees.  I have never heard them called ground bees.  There are many species of
bumble bees which are in the Bombus group.  They are fairly large, rounded and
furry.  Other bees and wasps also nest in the ground but do not present this
appearance.
Honey bees are the only insects apart from ants that over winter as a colony.
All the others rear a quantity of fresh queens in the late summer and the
nests are then dispersed.  The workers and drones die and the new fertile
queens hibernate individually in crooks and nannies.  The survivors will each
attempt to start a colony of her own in the spring to re -start the cycle.
Some species take over an old mouse nest as a ready made home and can find one
by the smell.
 If you want to have bumble bees in the garden first find a child who keeps
pet mice. Beg, borrow or steal the old nest material and in the spring when
you see the first bumble bees flying put the nest material in a half buried
inverted earthenware flower pot.  Do several and this will increase your
chances of success.  Watch the bees searching for nest sites to see the sort
of positions they prefer.
The bees are not flying from the nest now because it has been abandoned.  You
will be able carefully to dig it out to see how it was constructed.  Fill the
hole to prevent it being re used by mice and subsequently more bumble bees.
Enjoy your bumbles.
Chris Slade