Hi, Deb. What a great bed! I love the use of strawberries as a ground cover between the roses.
The only roses in my garden that never get black spot are Playboy and Cinco de Mayo. Also, Ping Lim's roses don't get black spot here, but the only one you're likely to find locally is Rainbow Sorbet.
Rose (Rosa 'Playboy')
Floribunda Rose (Rosa 'Cinco de Mayo')
Rose (Rosa 'Rainbow Sorbet')
Any Kordes rose also does better in my climate and will stay relatively free of black spot.
There are no mildew problems here, so I can't address that part of your question.
Aphids are easy to control without chemicals. Just knock them off the plant with a spray of water from your garden hose. They're incapable of climbing back up. If there aren't too many, you can also just run your fingers up the stem and bud and squash them.
