Bearded Iris Planting Guide
Bearded Irises are some of the most popular perennials in gardens throughout the world, and we’re not surprised! The endless array of colors and sizes makes them a versatile and show-stopping element of any garden. They are loved by many because they are easy to grow, deer-resistant, they multiply each year. Some are re-bloomers, putting on a colorful show in the garden twice in one season. Here are several tips to make sure your new Irises get acclimated to your space and become a mainstay of your perennial garden!
Read on to learn more about planting Bearded Irises:
All About Bearded Iris
Bearded Iris (Iris germanica) is a member of the genus, Iris, named after the Greek goddess of the rainbow. As the myth goes, when the gods wanted to communicate with humans, they sent Iris, who arrived with golden wings. As she stepped to earth, colorful flowers sprung forth. It’s almost hard to imagine a better name for this kaliedoscopic species! With thousands of colorful combinations, Bearded Iris is one of the most popular garden perennials. With endless choices of color, texture, pattern, and form, this flower opens the doors for garden creativity.
To communicate clearly about Bearded Iris, it’s helpful to know a little nomenclature.
- There are six petals. The three upward reaching petals are called “standards,” and the three petals that drape downwards, are known as the “falls”.
- The most distinguishing feature of Bearded Iris is their fuzzy "beard" located at the upper base of the falls.
- Bearded Iris grow from rhizomes - bulb-like, tuberous roots, with a fan of elegant sword-shaped leaves.
Bearded Iris Bloom Times
Bearded Iris comes in several size ranges with differing bloom times.
- Miniature Dwarf Bearded Iris are tiny, ranging in size from 5-15 inches tall. These great for a rock garden or border.
- Standard Dwarf Bearded Iris range from 8-16 inches. These are great with later blooming tulips.
- Intermediate and Border Bearded Iris grow from 16-27 inches.
- Tall Bearded Iris grow from 28-48 inches tall. These blooming from late spring to early summer with large flowers.
Actual bloom times will vary, depending on the weather. Each flowering stem will hold several buds that will come into bloom sequentially, usually lasting 3-5 days. Once it is finished, simply snap it off with your fingers to keep a clean look and to keep more flowers coming. After all the buds have bloomed, cut the stem back near ground level.
Where to Plant
Bearded Iris prefer at least 6-8 hours of sunlight a day. In hot climates (zones 8-11), they will tolerate 4-6 hours of sun. Make sure your Iris get some shade during the day in hotter climates. Bearded Iris prefer to be planted in well-drained soil. To improve drainage, they can be planted on a slope or in a raised bed.
What To Expect
Your Bearded Iris roots/rhizomes will arrive with the foliage trimmed from the past season's growth and starting to turn brown. The foliage can be trimmed when you plant, but leave at least a few inches of old foliage on the rhizome. It will be replaced next spring with deep green leaves.
What exactly is a Rhizome, anyway? The rhizome is the horizontal stem from which certain types of plants grow. Rhizomes are known for their ability to spread rapidly.
Basic Planting Steps
Step 1: Build up a small mound of soil in the center of the planting hole. As long as you have well-drained soil, Bearded Iris should thrive in your garden.
Step 2: Center the rhizome in the mound, roots down, and then bury it about 75%, leaving the top exposed. We recommend planting 12-24 inches apart, as planting too close together results in poor flowering. Plant rhizomes at the surface of the ground. The tops of the rhizomes should be visible; be sure to spread the roots out below the soil. The most common mistake made when planting Bearded Iris is planting them too deeply, which can result in few or no flowers.
Step 3: Firm the soil around the roots. Newly planted rhizomes should be watered thoroughly. This helps to remove any air pockets in the soil and gives Iris a better chance of strong growth.
The most common mistake made when planting Bearded Iris is planting them too deep. Planting too deep will result in few or no flowers.
Aftercare
- Before flowering, water plants occasionally to keep the soil moist but not soaking.
- Reblooming Iris should be watered during the summer, while Spring-flowering Iris will tolerate drought. Once established, Bearded Irises do not require regular watering.
- Be sure to keep your garden free of weeds and other debris to give your Iris as much sun as possible.
- Plants that are growing well (good green foliage) may not need fertilizing. Reblooming Iris should be fertilized in the spring as new growth begins, and after spring flowering ends. If you fertilize, apply ½ cup of 5-10-10 fertilizer per Iris clump after flowering. Fertilizers can burn the rhizomes; they should be applied around but not directly on them.
- Irises perform best with shallow (1 to 2 inches) cultivation (meaning shallow planting) and should not be mulched.
- After flowers fade, cut flower stalks back to an inch or two above the rhizome to prevent seed formation.
- For Reblooming Iris, after the second bloom fades in fall, cut leaves 6 to 8 inches from the ground, especially if foliage disease occurs.
- Every 3-5 years, divide your Bearded Irises (see below).
How to Divide Bearded Iris Rhizomes
After 3 to 5 years, Iris generally become crowded and should be divided. Iris can be divided at any time, but many growers prefer to divide 4 to 6 weeks after the flowering period.
Basic Steps to Divide
Step 1: Cut the leaves to one-third their length.
Step 2: Dig the clump of Iris up. Wash Soil off with a hose.
Step 3: Cut rhizomes apart so that each section has at least one healthy fan of leaves and firm, white roots. Older rhizomes should be discarded since they have limited flowering capacity. (New growth will protrude off an older rhizome from the side.)
Reblooming Bearded Iris
Many new hybrid Bearded Iris are offered as rebloomers. This means the Iris will bloom at its usual bloom time in the spring, and then come into bloom again at the end of the season, towards fall. The plant will grow new fans of leaves, putting up fresh flowering stems. It’s important to note that reblooming is not guaranteed and can be affected by location, sunlight and even the weather.
Reblooming Bearded Irises grow faster than regular irises, so unlike the standard bearded iris, you'll need to divide them more often. To prevent overcrowding, divide re-blooming iris every 2 to 3 years, take only the outside rhizomes of the plant. Leave the healthy older portions of the plant intact. Replant the small rhizomes 12 to 18 inches apart.
Rebooming Bearded Irises are not always guaranteed to bloom. It often depends on geographic location, soil, and climate conditions. Reblooming Bearded Irises can also vary from year to year. They are heavy feeders, requiring a little more water and fertilizer because they need an extra boost to flower again. Re-bloomers require a little more care than the standard bearded iris but are worth the effort.
To learn more about the different varieties of Irises, please read our in-depth article: All About Irises.
