Guernsey Cream is known for being a very early blooming clematis. I'm not sure there is any practical way to either delay clematis flowering or bump up the rose bloom - these are just two plants not in sync with their typical flowering schedule. Maybe move the Guernsey Cream and replace with a later flowering type?

FWIW, over the years I've found gardening life to be much simplified and more rewarding if you let plants be what they want to be and not force them into atypical behavior. Just saying.....:-)

Thanks gardengal, this is what I'm beginning to see!