Other than a few ornamentals that were growing here when we bought the house, I have only planted things that are useful or native. Yet I still have plenty of flowers and color! Many ornamentals have uses, we've just forgotten them.
Some collections are: irises (dark purple for dyeing, white orris
root for perfume, and various native Pacific Iris hybrids); columbines (various large single blooms, trying to encourage a mix of colors, all can have the nectar sucked out of the spurs); Campanula (all have edible flowers and leaves); alliums (there are many species that are cultivated for food, and all are lovely and all are edible).
One breeding
project I've been doing is new colors of California Poppy. It's one of my favorite
medicinal plants, but I'm not a fan of orange. So I was pleasantly surprised when a creamy yellow one appeared in my
yard. The next year an orange one with a red blush appeared, and I started pulling all the wild type ones and leaving only the lightest and reddest flowers. White flowers started appearing amongst the creamy ones, and the red blush kept increasing on the red ones. Then last year, the red and white genes came together in the same plant and I got pink flowers! I am now mostly selecting for any flower that has both a creamy or white base, and any amount of red blushing. It's a mix of coral, peach, and pink colors. Really lovely! This year, I found a new mutation: sepals that are lacy like the leaves! I may have to encourage these too.