I just bought a black lace elderberry, and it wasn't until I got home that I started to wonder if I need two for berries. Is this necessary? If it is necessary, how far apart can they be and still cross pollenate?

Also, I'm trying to replace my invasives with more native plants. I read on the tag to the black lace elderberry that it can be pruned as a hedge. Does anyone have a link or photo that shows this? I have some barberries I want to pull out and replace, possibly with elderberries. If this isn't a good idea, please someone let me know before I buy more of these plants!

Thanks for any advice regarding elderberries!