Plant of the Week: Siberian Iris

Let's take a look at Siberian irises.

I love Siberian irises. When we moved into our current home four years ago, I was delighted to find a huge (overgrown) clump of purple Siberian irises in the front yard. From that one clump, I've now got nine nice-sized clumps scattered around my garden, as well as given a few clumps to friends and family.

About Siberian Irises:

Botanical Name: Iris sibirica

USDA Hardiness Zones: Siberian iris is hardy in zones 3 through 10

Sunset Zones: 1-10, 14-23, 32-45

Description: Siberian irises have grass-like foliage that stays attractive even after the blooms have faded, giving a bit of texture to the garden. The flowers on Siberian irises are much smaller than those of bearded irises, and come in a range of colors including violet, white, pink, and blue. They grow from tough, fibrous rhizomes.

Size: Plants grow to around two feet tall and typically spread up to three feet.

Preferred Conditions: Siberian irises prefer full sun, but will handle light shade. Moist, fertile, well-drained soil is a must, and additions of plenty of organic matter in the form of compost, manure, or peat will make your irises thrive.

Planting: Plant Siberian irises in spring in northern regions. In areas that have really hot summers, such as the southern Midwest, Southeast, or in the Plains States, plant them in September.

Care and Maintenance: Siberian irises are easy! If you choose to fertilize (which isn't really necessary) simply apply a balanced fertilizer in early spring. Mulch the plants to conserve moisture and discourage weeds. Remove the flower stalks after the plants are finished blooming. After the first hard freeze, the foliage will turn brown and fall over. At that point, cut if off to a few inches above the soil. Clumps don't really need to be divided, but they can be divided every three years or so. While Siberian irises prefer moist soil, short dry spells don't seem to bother them too much. During long stretches of dry weather, try to give them an inch of water every ten days or so, and they'll be fine. Siberian irises have few pest and disease problems. The iris borers that so often plague bearded irises are much less of an issue with Siberian irises.