Looks like shot hole, a disease very common to many members of the Prunus clan, including cherries. It tends to be more cosmetic than not....primarily just unsightly.

Prunus shot hole disease

Thanks gardengal48. I think you're right! The article you posted said that it tends to occur in wet and warm springs and that's what we've had. Thanks so much for helping me out!

It is pretty much an annual occurrence here :-) Wet and warm describes our springs to a T!! But it tends to be concentrated more on purple leaf plums and English laurel, less on the cherries.

a damaged leaf can do all the work it needs to do.. as long as its green.. and mostly intact...

imo.. there is no need to treat this tree ... the leaves will fall off in fall.. and hope it doesnt happen again next year... which it probably wont.. since you are mystified by it this year.. as in you never saw it before.. or at lest didnt notice it.. so how big a deal can it be ...

ken