How to Grow Bearded Irises That Bloom More Than Once a Season

Best Bet Bearded Iris

For best results, plant your irises within a few days of delivery. The sooner your plants are in the ground, the sooner they will begin to grow and establish themselves in your garden. If you need to delay planting for a few days, store your irises in a cool place and mist the roots with a little water daily.

Irises look best when planted in groups within a garden bed or shrub borders. They don't like to be crowded, so choose a location where they have some room to spread. Irises perform best when planted in well-drained soil, in a location where they will receive at least six hours of sunlight per day.

Irises can remain in the same location for several years, so it's worth taking a little extra time to prepare your soil to ensure years of beautiful, productive plants. To prepare the soil for planting, dig a hole, about 12 inches deep and 12 inches wide, and loosen the soil in the hole. Add about four inches of compost (or other organic matter) and a handful of granular, slow-release fertilizer—such as Performance Plus. Thoroughly mix the fertilizer into the planting hole. The addition of organic matter and fertilizer will improve fertility, drainage and overall soil health. Once the soil has been prepared, level the surface with a rake.

To plant, dig a shallow hole that is about 10 inches wide and 2 inches deep—allowing one square foot of space for each rhizome. Next, make a ridge of soil in the middle of the planting hole. Set the rhizome on the top of the ridge, spreading the roots to both sides. Cover the roots with soil, but leave the top of the fleshy rhizome exposed. Firm the soil around the roots with your hands. As the irises becomes established, some of the soil will be washed away, and the rhizome will become more exposed. This is normal. In fact, irises will not thrive unless their rhizomes are exposed to the air and sun. As you're planting your irises, it's a good idea to align the rhizomes in the same direction—with the fans of foliage parallel to each other. This will create a better overall appearance in your garden.

Reblooming irises may take a full growing season to establish themselves before producing their first blooms. You should expect healthy green foliage the first spring and beautiful blooms the following year.

Watering: As your irises are getting established in your garden, it's important to water them regularly. Twice-weekly watering, for the first few weeks, is a good idea. Be sure to avoid over watering, irises can rot if they are sitting in water. After they are established in your garden, they will not require supplemental watering except during periods of drought.

Customer photo by Susan of Washington, N.H.: The front of our house is landscaped with giant boulders moved from the site of our foundation. This shot of an Immortality reblooming Bearded Iris was taken first thing in the morning with the dew on the petals.
See the full-size photo	Go to the Photo Center and see more images from Dutch Gardens customers.

Summer Care: Reblooming Irises flower in the spring when other irises are blooming, but they are special because they have a tendency to send up additional flowering stems in August, September or October. In warmer climates they may even bloom continuously throughout the growing season. The spring blooming period is usually the most floriferous. To encourage reblooming in late summer or early fall, apply a slow-release flower fertilizer—such as Performance Plus—after spring blooming is complete. Be sure to provide regular water when rainfall is insufficient. Reblooming irises are not guaranteed to rebloom every year. Performance will vary due to growing conditions, climate and weather patterns.

Dividing: Irises benefit from division every four to six years. You can tell it's time to divide if your plants appear crowded, if you notice decreased flower production or if the center of the clump appears to be deteriorating. The ideal time to divide iris is in August. Dividing them in the late summer will give them the opportunity to reestablish a good root system before the winter. Clumps may also be divided in the early spring, but flowering may be sacrificed for that season.

To divide, loosen the soil around the clumps and gently pry the entire clump from the soil, retaining as many roots as possible. Divide the clump into portions with a clean, sharp knife, making sure each new piece of rhizome has plenty of roots and one to two sets of leaf fans. Remove any dried or withered foliage so only healthy, fresh-looking foliage remains. Trim the foliage with a scissors into 3-4" tall fans. The rhizomes on the outside of the clump are younger, healthier and more vigorous. Discard the older rhizomes from the center of the clump. Plant the new divisions following the previous planting instructions. Be sure to water thoroughly as the new divisions are reestablishing themselves, but avoid over watering.