Weeping cherry blossom trees are known for their cascading colors and graceful shape, but they take a little bit of maintenance to keep their shape and prevent pest and disease problems. Weeping cherry blossom trees are either natural or grafted, and you will have to know which you are growing before you begin pruning or you could damage the tree and slow the growth. Grafted trees have a graft knot below the crown, several feet up from the base of the trunk. Natural trees will have no graft knot.
Cut off any branches that are growing below the graft point on the trunk. These branches are called water sprouts or sucker branches because they suck the water from the tree and prevent nutrients from being spread throughout the weeping branches. Natural weeping cherry trees will not produce water sprouts.
Remove all dead or diseased branches, as well as any branches that are crossed and rubbing. Crossed branches can cause wounds that open the tree up to pest and disease problems.
Prune off any branches that grow straight up on grafted weeping cherry blossom trees. Prune them while they are small so pruning scars are not as noticeable and so that the wound is little and quicker to heal.
Thin out branch snarls that may form on the crown of the tree on grafted weeping cherry blossom trees. Keeping snarls from forming will allow better air circulation and more light to get through to the rest of the tree.
Trim weeping branches to keep them off the ground. Keeping them 6 to 12 inches from the ground is recommended if you aren't using mulch and must mow around the tree. Trim to all the same length for a neat look, or use a staggered approach to maintain a more natural look. If you leave them intact, consider using mulch around the perimeter so you don't have to mow around the weeping branches to reduce the potential for injury