Iris flowers have been a favorite part of many garden landscapes for centuries. The Iris flower is a bulbous or rhizomatic perennial plant. The iris group is large and has irises that bloom in winter, some that bloom in the spring and others that will flower in the summer. The roots of all of them are fleshy with some more rhizomatous and other iris that look more like true bulbs. Iris flowers have thin, upright foliage that adds a vertical accent to any container garden, bulb garden or mixed border planting. The grass-like foliage is thicker than most ornamental grass blades but still adds that movement to a landscape when planted in a mass. Various Iris bulbs do best in different areas of the landscape, allowing gardeners to use iris flowers in almost every area of the garden, no matter what soil conditions they have to work with.