Every once in a while something shows up in my gardens that truly leaves me baffled

Just now I was outside filling the Ferals food dishes and something white caught my eye, by the apple tree. I got a little closer and saw what LOOKS like a Butterfly Bush growing where I've never planted anything because the neighbor's honeysuckle and clematis have already taken over the fence in that little corner of one of the gardens. It's not even like Butterfly Bushes (if that's what it is) spring from random seeds contained in bird poop. And it appears there's more than one, growing in that spot. One is pretty large, yet this is the FIRST time I've ever seen these blooms, and I'm in and around that area a lot because it's next to the veg garden.

So, yea, I'm baffled but ALSO delighted. I might try transplanting a small one. If anyone can confirm or correct my identification, I will be grateful.