When Do Irises Sprout?

Typical Sprouting Period

• Depending on the iris variety and local climate, you should see foliage sprouting between March and June. Flowers commonly follow visible foliage growth approximately 3 weeks afterward -- the new leaf growth provides the energy necessary for spring blossom development. Rhizomes have multiple bud points along their surface, allowing dense foliage and several blossoms to grow upward in optimal conditions. If you have a small rhizome, such as a division from a larger underground stem, it is possible to have no blossoms the first year. In fact, you may simply have a subtle display of iris leaves. Your immature rhizome needs to grow and store more nutrients for flower development the following spring. In contrast, some iris cultivars have the ability to sprout more blossoms in the summer and autumn. But rhizomes are often spent by this time, and flowers are not as spectacular as the first growths.

Planting Strategy

• Your irises cannot sprout unless they are planted correctly in the soil. Commonly planted in the summer and fall, iris rhizomes do not acclimate well to deep soil surroundings, like typical flower bulbs. In fact, you need to form a soil mound that provides a perching point for the rhizome -- it should be slightly above the soil's surface for air circulation. A deeper planting suffocates and rots rhizomes while producing no sprouts during the growing season. Rhizome roots should hang to the sides of the mound for moisture absorption as the perennial iris is exposed to some sunlight at the soil surface.

Moisture Influence

• To encourage normal, late spring sprouting, maintain a moist soil environment around your planted rhizome. Once the roots acclimate to the soil by producing new leaf shoots above ground, you should reduce your watering frequency. For instance, use a moisture meter to detect when the soil is dry down to a 3-inch depth. Water your irises at this point to maintain healthy root growth while preventing rhizome rot.

Fading Leaves and Dormancy

• For most iris varieties, the summer months of July and August are dormant periods; new sprouting stops and foliage begins to die back. To encourage prolific sprouting next season, allow the leaves to fade until they are yellow and papery. Although your iris blossoms may be long withered, the leaves continually photosynthesize until they are completely decayed. The energy produced is stored within the rhizome for maximum sprouting potential the next year. Removing the leaves causes poor foliage and blossom sprouting -- you may not see any growth if the rhizome does not have the energy to create new leaves and flowers.