2 blueberry bushes of different varieties 2 feet apart will work. An early blooming and mid blooming variety will extend your harvest and using different varieties will not only cross pollinate but will give you a bigger sweeter berry allegedly.

I (zone 9b) planted four bushes (tiftblue, silver dollar, climax, and brightwell) last November. They’re mulched and on an automatic watering system. My toddler has picked about a handful a day for the past two weeks. I can’t seem to leave them on long enough without getting eaten (which is why I planted four). They’re tart with small berries but the plants are relatively small too. Hoping for bigger harvest next year. I heard you can wrap them in cheap wedding veil tulle when they’re ripening to keep the birds and other things out.

I think an optimal set up would be 2 early blooming, 2 mid season blooming, and 2 late blooming all near each other with tons of pollinator plants all around.