Those tall purple spires are Cupid Culver's Root. It is a perennial which grows vigorously in my zone 7b North Georgia mountains garden. The first year, it grew to only about 2 foot tall, but the second year it grew to 4 feet, and this year it is over 5 feet tall with lots of branching. I have also seen this plant growing and blooming vigorously in the Alaska Botanical Garden in Anchorage.
