Looks like they needed to be hardened off before planted outside.just keep them shaded from direct sun ..slowly release the covering in a few days they will harden up to outside temps and exposure. Sometime s the dry soil around the root ball will wick the water from the roots. Try soaking the planting hole first , and check the drainage. Be sure the roots don’t sit in water. the soil looks a bit dry and clay and maybe adding some amendments to the soil will help the roots adjust too it’s new home and keep the roots moist during the hottest time of the day.