Now, just after the flowering period, is the best time to trim your weeping cherry. They form the buds for next spring’s flowers over this summer. If you prune later in the season, you’ll be pruning away the buds and won’t have as many flowers next spring. Weeping cherries are grafted (with two grafts). Prune away any suckers at the base of the tree whenever you see them sprouting since they are robbing energy from the upper part of the plant. The top, weeping part of the tree is also grafted to the main trunk so look for any branches that are trying to grow from the trunk below that upper graft and remove them whenever you see those. They won’t weep and, if you let them go, they will grow faster than the weeping upper part and take over. In other words. prune away any shoots are branches that are growing anywhere below that upper graft. Never prune away more that 1/3 of the desirable weeping branches each year to avoid shocking the tree.
If your grass hasn’t shown any signs of life by now, I’d assume it is dead.