Hi, yes you can plant in the ground now, I would stand it in a bucket of water for half an hour or so, to give it a good soaking, then plant in the garden, give it a good watering in, this helps to fill in any air pockets that may have been created while planting, keep it well watered, especially if the hot weather continues, if the plant is potbound, which it sounds as if it might be, get your fingers into the root ball slightly, and prise the roots out of the root mass and spread them out, Derek.