6 hours IS full sun, so that should not be your issue. When you said morning only I was thinking only a couple of hours. You can look them up on Proven Winners website it says how to care for them, yes they are full sun. I have limelights (same kind different name) in full on sun ALL day and they about 7 feet tall this year and loaded with blooms. You can look it up on a search if you want to know more.
Did you prune them at any time? And were they pruned back when you bought them? I order things from proven winners mail order, and they often cut off the plants to pack them, depending on when you prune them, they may have lost this years blooms.
Other than that, they look fine, and patience is all that is missing, if they don't bloom next year, then you have a problem.
