Some of the most popular perennials to grow in the garden, iris are loved for their showy flowers that add elegance to garden settings and cut-flower displays. Gardeners can choose from many types of iris including German iris, Dutch iris, Japanese iris, Siberian iris and Louisiana iris. The iris varieties have different bloom times, ranging from late spring to midsummer. Most iris are low-maintenance, easy-care perennials that grow best in full sun or partial shade. German iris are able to handle drier conditions while Japanese, Siberian and Louisiana iris are favorites for planting near water features. When buying iris bulbs for sale, some factors to consider are hardiness zone, light requirements, water needs, mature height and spread, flower color and bloom time.