#TeachingTuesday: Plant of the Week—Bearded Iris
Irises have captivated human interest for thousands of years, from ancient Egypt where it was used by pharaohs as a symbol of power, to ancient Greece and Rome, where the name of the flower originated from the goddess of the rainbow, Iris. More recently, irises have been painted by many famous artists, such as Vincent van Gogh, Claude Monet, and Georgia O’Keeffe. The iris is also the symbol for the outstanding Sarah P. Duke Gardens, at Duke University in Durham, NC, and that is because the oldest part of the gardens—the terraces—were originally planted with irises. The modern hybrid bearded irises mainly came from breeding efforts that started around 1902 and continues through today. The common parent in these hybrids is Iris germanica, and today most of these hybrids have extremely complex genetic heritage and are simply referred to as Iris x germanica.
Planting and Maintenance
Bearded irises are very low maintenance, and easy to grow in the right soil if they are planted correctly. Bearded iris grows from thick root-like stems called rhizomes, which must be planted at or just below soil level. In cooler climates, the rhizome can be planted half in the soil, half above the soil. You may need to use stakes or garden staples to keep the irises stable until they root in. When mulching bearded irises, make sure you don’t mulch on top of the rhizomes, or use just a thin layer of very fine mulch, such as pine fines or leaf mulch. The leaves should not be cut back until late fall, or they will not produce good flowers for the following year. Clumps of iris need to be dug up and divided every 3-5 years in order to continue blooming well.
ID Tips
- The leaves are flat and sword-shaped, and they grow from a fan at the base of the plant. They may have a grayish or blueish waxy layer. They are distinguishable from daylily because they are much larger and do not have a crease along the center of each leaf.
- The flowers may be almost any color imaginable. The flowers have three upright petals (called ‘standards’), and three lower petals (called ‘falls’) that fall downward. The lower petals will all have thick, bushy “beards”.
- The rhizomes are a light tan color, and look somewhat like ginger root—a thick, fleshy, root-like stem that branches off new little rhizomes each year.