Hi Garfield and welcome to GoY. This is not a good time of year to transplant anything and a 3 foot high broom bush is going to have a large root ball, leave until autumn if you need to move.

Hi, as Moongrower says, now is not a good time to transplant anything, in fact there is never a good time to transplant a broom, they resent being moved, it would be better to buy a new young plant in a container, as they can just be planted out, without disturbing the roots, Derek.