I live in Ohio in Zone 5; my son lives in Kentucky, and his weather
seems very similar to ours, so I would guess that weather is not why
they don't do well there. I wonder what the reason is?

Any way, we have had a sweet cherry tree (Stella variety) for over
twenty years and it has been doing quite well. It is self fruitful, so
you don't need two of them, and produces a nice sweet cherry that is
very like a Bing, but we often picked them before they were fully ripe,
before we learned that red is not ripe, black is.

Kentucky Di wrote:

I would like a sweet cherry, but our county extension agent here says
they just do not do well in Kentucky. Does anyone know of a type of
cherry that would do well here?