Especially with some fruits that come in many different varieties, it really matters to find out which varieties are needed for it pollinate.
Most blueberries fortunately, I think tend to flower close to the same time of year, but not always.
My friend has a tiny one called Jelly Bean that he grows in a container on his porch, and says it self-pollinates well, and his kids love picking fruit off it. I've had one growing in my yard for three years, it is still scrawny, and it has never formed fruit. Ha!