No doubt you've heard that a well-designed garden should include plants prized for their striking foliage, as well as some that produce fall color or berries, and others that provide good structure in winter. But lets face it: most of us want flowers. Lots of them. All the time. That's where the plants listed below come in. They'll churn out blooms for weeks on end this summer. In most cases, you can harvest armloads to fill vases or give away, and still have plenty left to enjoy in your garden beds long past Labor Day.Also known as rose-mallow and swamp hibiscus, this garden standout was bred from wildflowers native to the East and South. Huge red, pink or white flowers can be as much as a foot across on stems that range from 2 to 8 feet high, depending on the variety. Flowers bloom from late spring until frost. Stems die back to the ground each winter.Before 1995, when this hybrid was named an All-America Selection winner, gardeners thought of petunias as upright plants. Purple Wave petunias (and later Wave introductions in pinks and lilac) are more like vines—perfect for growing in hanging pots, along retaining walls or even as a ground cover.Grow zinnias if you want to be able to cut armloads of flowers for bouquets and still have a bright band of color alongside a path or a lawn. All zinnias thrive in hot weather, but Profusion zinnias keep on blooming well into fall, whatever the weather. Profusion White, Orange and Cherry, which have daisy-like flowers, each have won multiple garden awards. If you want fluffy pom-poms, look for double Profusion varieties in cherry, gold, white and "fire," an orange-red.