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!

Bearded Iris are classified into several types: miniature dwarf (height 8 inches or less, 1 to 2 inch diameter flowers), standard dwarf (height 8 to 15 inches), intermediate (height 16 to 27 inches), miniature tall (height 16 to 25 inches, small flowers), border (height 16 to 27 inches), and tall (height 28 to 38 inches). The shorter Iris flower first, followed by the intermediate, and then the taller Iris.

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.

bearded iris rhizome visual identification graphic

How To Plant: Soil Prep & Depth

Correct way to plant bearded iris into soil graphic

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.)

drawing demonstrating how to divide plants

Reblooming Iris Notes

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.