Lobelia laxifolia, offsets obtained before the gardener at a local business dug it out of their perennial border. I had no idea what it was at the time but it was a splendid affair, growing fountain-like, lush, over five feet tall and smothered in the blossoms you see here. My little guy in the photo is only about 10 inches tall but I have great hopes based on parent plant.
(How about that lovely exposed irrigation pipe? I'm working on it, really I am.)