Does Anybody Really Know What Tree It Is (Does Anybody Really Care)

OK, so I was driving to Winston Salem and back on new I-40 yesterday and over the space of a few miles on either side of the Guilford/Forsyth County line were these small trees with very bright clusters of what seemed to be upright purple flowers. They were really quite eye popping. I was only able to glance at them as I drove by at 65 miles an hour, but I seemed to be able to discern, 1) that they were legumes – seems there were drooping seed pods hanging from last year, 2) that they were stout little buggers, 3) that they were maybe ten to twenty feet high max, 4) that the flower clusters were upright and not drooping (seemed that way from a distance), and 5) that the flowers were very bright purple, really quite stunningly pretty. I thought maybe wisteria at first but the stoutness of the stems and the uprightness of the clusters seemed to rule that out. Then I thought of black or honey locust, but I’ve never known of a purple locust – is there one? And locust clusters droop. These flowers looked more upright, like catalpa. But I’ve never heard of purple catalpa. So, I’m stumped. Any of you botanists or gardeners out there have a clue what these really delightful purple blooming trees might be?

Joel