I plant three huge Rex begonias right into the bed, and move two large mixed planters of geraniums and Abutilon and fuchsia into the bare areas. Instant color where there was only bare soil. They won't live through the winter, but that's OK. They'll color it up and act as placeholders until frost. It's cheating, sort of, but it's good cheating.
In late summer, the sun's intensity has dropped enough that I can bring my bonsai Japanese maples out of the shade and display them on the front stoop. I love to watch them color up come fall.