I have a nursery bought dwarf Alberta Spruce, 3.5' tall, in a plastic pot. I live in Grand Rapids, Michigan. I want to turn this tree into a more traditional upright bonsai tree which will require lots of pruning and wiring. I am not sure the best time of year to do this work. I'm assuming that it will be early spring, but having no experience with this species, I would appreciate some guidance. Thanks for your time .