I never prune any fruit young fruit trees for at least 3 or 4 years. It isn't necessary even for an ornamental crab apple to start shaping till then. Pruning simply slows down root development as the tree tries to replace branches instead of building a healthy root system.

Sarraceniac

Sincere thanks for your advice and information about not pruning my crab apple. I'm grateful because I would have made a serious mistake otherwise.

Many Thanks

Best wishes
Primavera