Q.Weeping Cherry leaves
Weeping Cherry only has green leaves on 1/4 of the tree. I noticed that about 1/4 of the tree lost its leaves VERY early. This spring the whole tree blossomed, but not as much as usual. After the blossoms left, only 1/4 of the tree actually has green leaves. What can I do to help it?

With the below normal temperatures this past winter that nearly the entire United States endured, many trees, plants and gardens are seeing the results of some damage and worse.
Here is a link to Weeping Cherry care. Make sure your providing adequate water to the tree and a slow release fertilizer would be helpful.
https://www.gardeningknowhow.com/ornamental/trees/weeping-cherry/weeping-cherry-growing-tips.htm