I budded many apple trees last summer. Most of them worked well and are growing nicely right now. However, a handful of them are still dormant. The bud graft union is well healed over and the bud looks viable. I have even scratched a few of them and they are green, but they don’t seem to want to wake up. Anyone have any advice?, I’ve already cut the top of the rootstock off. Thanks for your time and experience