What is this bush?

There are two mystery bushes in the north border, and one is in bloom. It's a very shy bush, and now that it has bloomed, I understand why I didn't even remember that it was there.

It has an amazingly sweet, quiet scent. And I think, like the other things in this border, it may either be a transplant from some walk in the woods decades ago or it is an old-fashioned bush. If someone knows -- shout out!

Here it is April 30:

And here it is, today, in bloom:

p.s. Not to ruin the mystery, but now, in late May, it has little green blueberries, and so Nature speaks. It is a blueberry bush!