What fun! White really pops out in a landscape, so JFK could go in the back of a bed, and so could Mr. Lincoln because he gets tall.
I try not to have two rose bushes of the same color next to each other. It happens anyway, of course, because of mislabeling, but I do try.
I never worry about clashing colors, though. Nothing in nature seems to clash, even if I plant a red rose next to an orange one.