is moss on cherryblossoms a positive or negative attribute?

Answer 1

You have moss on the actual blossoms? I never heard of that but if they're still blossomoing, I guess it doesn't mean anything.

If it's on the branches, you could have a fungus called black knot. Cut off all affected branches, get a bordeaux mixture fungicide, and cut down any nearby chokecherry plants. Does it look like this?
http://ohioline.osu.edu/hyg-fact/3000/3011.html

.