Pruning Silver Birch
How and when do I prune the lead out of a silver birch to make it multi-stemmed.
Certified GKH Gardening Expert
You can do this at any time after it is 2 years old (unless you are doing it for bonsai, then it can be done sooner), Just nip the top of the terminal node (main trunk) off and this will force it to branch out. You don't need to take much. Just damaging the end of the terminal node is enough to stop it from growing, which means the tree must grow side nodes to grow upwards.