White Flowered Nectar Bush
Once again, I have to thank Mosaic at Current Events Garden Forum for giving me the ID on this plant: Thanks very much for all of your plant identifications!
This bush is very easy to share with your butterfly gardening friends. Just break off a branch, stick it in the ground, and it grows. That's how I got mine. I'm adding more to my yard this way, and so far so good, they're growing, and growing fast. I'm in South Florida, so I can't say how it will grow for you, but it's a very happy bush down here.
I needed a hedge to replace the Australian Pine Trees we're getting rid of, and I'm using this Chaya and Firebush to make it. They both grow fairly fast, neither should get tall enough to do serious damage when the next storm blows them over, they'll add privacy for us, shelter for the butterflies, make a nice trellis for more Passiflora host plant vines, and I can't wait to see the butterflies all over it when it matures. (The Firebush for that project is seeds in pots right now. Gardening is a process, just like my site, but little by little it evolves and matures.)
Please email me if you know what species it is.