September already?

Where did the summer go?  The weather starting to cool with temperatures of low 50s at night. The signs of fall are here! The highlight of our garden is the Autumn Clematis (Clematis Terniflora) which appears to be an aggressive grower ...which I like. I have it climbing over the Honeysuckle "Goldflame" which has been a  high maintenance climber for me. On the other side of the arch I am climbing another plant - a mid season Clematis "Comtess de Bouchaud".
I was wondering today: how many climbers are too many on the same structure? What do you think?