Hi Charles:
I'm not a big fan of fertilizing recently transplanted seedlings or nursery stock due to the simple fact that many fertilizers can "burn" the delicate existing and emerging root system. I'm not against fertilization, I just thinks it's unnecessary during the first two years after transplanting.
However, if you absolutely "must" fertilize your newly planted trees, then use a low NPK fertilizer blend such as 8-8-8 or 12-12-12.
Best of luck!