I just bought two dwarf blueberry plants for this season. I've heard from some that you need a "male" and "female" plant for pollinating and to help increase fruit output. Then there are others that say there's no such thing as male and female blueberry plants. What's your opinion?

I bought one dwarf northsky and one dwarf northblue plant. Any experiences with these two varieties? I'm in zone 5 so I wanted something that can handle the cold!

They'll stay in pots for the first 2-3 years then I'm transplanting them into the ground.