Water any new tree or shrub every week that rainfall is less than an inch. And don't do it by sanding there with a hose. Turn the water on very slow and let it ooze at the base of the plant for 30 minutes to an hour each tie. Another brand is Once. Keep weeds removed all the time, but digging about it isn't necessary.
Many people don' t know the best time to plant garlic is in the fall.
I removed the affected branch, but there remain a couple of areas of meldew on another part of the tree, on blossom and leaf bearing branches. I usually prune the tree back each fall. Mildew usually affects the leaves and buds of cherry trees, not the limbs. Probably a fungus of some sort, but I'm not sure what. Try pruning in winter, after the trees are domrant, rather than in fall.