Bearded iris (Iris germanica) is a hardy, long-lived perennial that require a minimum of maintenance. The flowers have six petals; three upright petals (called standards) and three hanging petals (called falls). A fuzzy line or beard runs down the middle of each fall. Flowers come in many colors including blue, pink, purple, reddish, white, yellow, and bi-colors. Most bearded iris flower in the spring (April to June depending on cultivar), but some of the new cultivars re-flower in the summer and fall. The second flower display is not as showy as the spring display but lasts into the fall. Many re-blooming iris are fragrant.

Growth Habit
Iris have thick, fleshy, underground stems (called rhizomes ) that store food produced by the sword-shaped, semi-evergreen leaves. The rhizomes grow best when planted at or slightly below the soil surface with feeder roots penetrating the soil below. Each year underground offsets develop from the original rhizome. Buds produce a large fan of leaves and several flower stalks. Success with iris depends on keeping the rhizomes firm and healthy. In general, this is done by providing the rhizome good drainage while the feeder roots below remain moist but not wet.

Site Selection and Preparation
A full sun exposure is preferred; however, some of the delicate pink and blue iris hold their color better in partial shade. Excessive shade will reduce or prevent flowering. Good soil drainage is essential to prevent rhizomes from rotting. It may be necessary to plant the rhizomes in raised beds (at least 6 inches high) to obtain proper drainage.

Fertilization of iris is important to obtain best results, but must be done in moderation. Nitrogen, potash, and phosphorus are essential for iris, but excessive nitrogen promotes lush growth that is more susceptible to rot diseases. At planting, incorporate ½ lb of a low-nitrogen fertilizer such as 5-10-10 per 50 square feet (1 ½ oz per 10 square feet). Taking and following the results of a soil test is the preferred method to determine fertilizer amounts.

Planting
The best months to plant bearded iris are August and September. This will allow them to become well established before winter. Container-grown iris can be planted in the spring. In a well-prepared bed, dig a shallow hole large enough to accommodate the rhizome or clump of rhizomes. Form a mound of soil in the center for the planting base. Make the mound high enough so the top of the rhizome is slightly above soil level. Spread the roots around the mound, fill with soil, and water. For a mass of color, plant at least three rhizomes (spaced 8 to 10 inches apart) or plant undivided clumps; point each fan of leaves away from the center of the group. Clumps should be spaced 18 inches apart. Mulch should be applied to fall-planted iris to reduce heaving during the winter.