This Japanese Weeping cherry has developed a split and several of the limbs are starting to grow up and not down. What can I do?
Most weeping trees are grafted. Most likely the limbs growing up are from the lower portion or root stock of the plant. Prune out the upright branches, and continue whenever they re-occur.
The crack may be a grafting compatibility problem between the weeping scion and the root stock. The wound (crack) is trying to seal itself off, so do not put any wound dressing on it, and do not wrap it. Continue to give the tree good maintenance by keeping it watered (1 inch per week).
Cherries are generally short-lived trees- 15 to 20 years is a long-lived cherry tree. In addition, with the tree being stressed, it is susceptible to borers so you may want to consider a borer treatment. You will treat the tree starting at the base and treat all the way up to the weeping portion of the tree. Make the first application from late May to early June with a couple more applications about a month apart.