A
tree that self pollinates will give you fruit but less than if you would have another pollinator. A flowering crabapple will pollinate an apple
tree but only if they are in bloom around the same time. Most times there is a neighbour within distance that has
trees which the bees tend to help you with.
I purchased a '5 in one' apple
tree because it pollinates itself from the different apple branches. It is my third year after planting and I had a few apples last year on it already.
Another question about planting two cherry
trees together? I wouldn't do it. There's not alot of room for your
trees to breathe(as they say)also if one
tree ends up diseased the other one ends up with it also.
Did you know that a sandcherry bush(cheap and pretty) can also pollinate your cherry
trees? I just found that out last year and purchased one to go with my cherry
tree in the backyard that never beared fruit. Guess what? I ended up with 3 cherries, hoping the
tree takes full force this year. Good luck.