I have a cherry tree in my garden which I grew from a cherry stone from a known fruiting sweet cherry tree. It as about 40 years old and 15/20 foot tall. It has fruits every summer but they are always very small, dry and sometimes bitter. We rarely have frosts during flowering but the land is dry sandy/loose gravel over clay. The garden is north facing and the tree is often in shade. I have tried everything from watering to mulching. Is it time I should cut it down and replace
Is your concern the flavor of the Cherries? The tree that you grew from an existing Cherry Tree stone, is likely not the same as the parent tree. It may be more like the root stock Cherry and the root stock is often a less palatable fruit tree stock.
There is really nothing to be done to change the fruit that your tree is growing.
If your looking for a tasty Cherry Tree I would suggest you check with your local County Extension Office for a list of recommended trees in your region.
Here is a link to help you locate your nearest office.