Jasmine growing outside
The leaves this year are a pale green instead of the usual dark glossy leaves. May I feed horse manure?
I would have care applying fresh, or uncomposted manure. This can cause the opposite of the problem you are having now. It would be best to apply a pre-mixed fertilizer, or if you have well composted manure, then this will be good as well.
Here is an article that will help: https://www.gardeningknowhow.com/ornamental/flowers/jasmine/how-to-fertilize-jasmine.htm