I'm not sure what the problem is either, but I guess that if you get beautiful blooms every year before they turn brown, I'd just cut them down after that. It may be something they'll grow out of, or it may be just their way. There are other plants that bloom and "die", like poppies and bleeding heart, and people on this forum have talked in the past about cutting their clemmies down after flowering and getting a second blooming. I don't think that will happen necessarily in our zone 5 gardens, but at least you won't have to look at brown plants for the rest of the season.

I think some are more predisposed to getting brown ugly leaves this time of the year..I have some that do and some that never don't...I find the ones getting the most sun do and I water them more often..but they still get brown leaves...ugly but doesn't seem to affect their bloom capabilities...don't you find they are generally pruning group 2s?..Jeanne

My Clematis does the same thing. Seems to be associated with the heat. It gets about 12hrs. of full sun. Once the temps. go above 80 consistantly, the leaves on the Clematis begin to turn brownish. It doesn't affect the plant in any negative way, though. It's been doing the same thing since planting and it comes back bigger and stronger every year. Still blooms and grows even with many leaves going brownish. I usually prune the brownish leaves off which causes the plant to grow more and bloom during summer months as well [mine is supposed to stop blooming by July].

Don't think there's anything to worry about.