Tough, bushy perennials that add color all summer long. All good gardeners love the Potentillas, and here's why. They cover themselves with stunning flowers from early to late summer, while most other perennials bloom just a couple of weeks. What's more, Potentillas are short (about 2 ft.) shrub-like relatives of the roses, and if you look closely, you'll see that each brilliant 5-petaled flower looks just like a single wild rose. They're great additions to any perennial garden.