Short answer: You'll have better production if you do.

My southern highbush; Star, Santa Fe, and Southmoon; set every flower whether they are pollinated or not. Maybe pollination would give larger fruit but I haven't seen a difference. I always prune and thin to get the fruit load down. So if only half set I'd be happy.

Northern highbush and rabbiteye may need pollination. I'm just getting into growing those.

They don't need a separate variety for pollination, but like Jean said, you'll have better production if there is another variety around. What "better production" means, is bigger/more fruit. If you have more varieties, you'll get more fruit at different times as well, so I say why not?

It would be difficult to picture a home garden with too many blueberry bushes. They are pretty and decorative as well as delicious. Plant a third bush of a different variety and then have no worries. In my own garden I have planted eight bushes of six varieties and I'm looking forward to wonderful fruit, provided the birds and squirrels don't get them all. I plan to net them when the fruit starts to ripen.

Rosefolly