Thanks for the quick responses. I live in central CT, zone 6. The site, a chain link fence is 100' long with 50% in full sun and some shade. 10 plants filled the fence by early August. I can only think that I gave the plants too much TLC, some fertilizer but not excessive, and they were just so happy sending out new growth that reproduction was not urgent. The plants are exploding in bloom now but frost is 4 days away.
