Perennials are plants that, once planted, generally return every year. Their roots remain alive under the soil through the winter and come up in the spring. These should be the backbone of an easy-care garden. Generally, they are in bloom for 2-4 weeks, depending on the plant. To get you started beautifying a Metro-Detroit flower bed, a list of the top ten easy-care perennials for shade in Michigan is set out below. "Shade" means that the flower bed must get a few hours of shade each day.