It was there when we moved in, and we've never watered it or done anything to maintain it.
But it gives such a pretty lavender pop of color in our backyard, and every morning when I look out the window while brushing my teeth, I see tons of butterflies on it.
Which now makes complete sense! I finally took the time to look up what kind of bush it is, and found out its common name is "Butterfly Bush."
Buddleia's literally explodes into a summer landscape with masses of 4" to 10" long cone-shaped flowers from July through September. Adding to the color are clouds of butterflies these flowers attract while open. (From here)
Do you have any flowers or bushes in your yard that attract butterflies?