FAQ's About Bearded Irises

04-09-2007

FAQ’s about Bearded Irises


When can I plant my iris?

You can plant your iris anytime before freezing temperatures arrive. For the best flowering results, planting is preferred in July, August, or September. It’s important to get the roots established before the growing season ends.

Where should I plant my iris?

Irises need at least a half-day of sun. They do best in full sun. Be sure to plant in an area with good drainage. Bearded iris do not like “wet feet”. They do well on slopes or in raised beds. If your soil is heavy, you can amend it with coarse sand or compost.

How deep should I plant my iris?

Irises should be planted so the tops of the rhizomes are exposed and the roots are spread out facing downward in the soil. A common mistake is to plant the iris too deeply.

How far apart should I plant my iris?

Irises are usually planted 12 to 24 inches apart depending on how fast you want them to fill in.

How often should I water my iris?

Newly planted irises need moisture to help their roots become established. Keep in mind that deep watering at long intervals is better than more frequent shallow watering. Once established, iris don’t normally need to be watered except in extremely dry areas. Overwatering is a common mistake.

What about fertilization?

Specific fertilizer recommendations depend on your soil type, but bone meal, superphosphate or any fertilizer low in nitrogen are effective. Nitrogen encourages rot. A light application in early spring and a second light application about a month after bloom will promote good growth.

How can I keep my iris healthy?

Keep your planting beds clean and free of weeds and debris, allowing the the tops of the rhizomes to bask in the sun. Bloom stems should be cut back close to the ground after blooming. Healthy green leaves should be left undisturbed, but diseased or brown leaves should be removed. Cut off and destroy any part of a leaf that is affected by disease. About six weeks before bloom begin a regular spraying program with a fungicide. Using two fungicides alternately is often more effective than using one exclusively. Above all, avoid overcrowding and provide good air circulation.

What should I do when my irises become crowded?

To ensure good bloom, divide the iris clumps every three to four years. In the late summer, dig up the clump; separate the new rhizomes and replant.

Should I mulch my irises?

Iris do not need mulching in our climate. However, if you wish to provide weed control and winter protection, use mulch that allows the water to pass through quickly. Also, pull the mulch away from the rhizome as soon as possible in the spring.

What should I do about soft, smelly rot?

It is very important to remove the rotting tissue as soon as possible. Remove the soil from around the rhizome, leaving the roots anchoring the plant. Carefully remove the mushy tissue. After removing the tissue, drench the wound with a 10% bleach and water solution. Allow it to dry thoroughly before covering with soil again.

My irises aren’t blooming. What can I do?

Make sure they are getting full sun. Divide large clumps. Only 60-75% of iris bloom the first year they are planted. Sometimes they need time to get established. Late spring frosts can also harm bloom.

Do irises change color?

I haven’t found any authority that can confirm that iris actually change color. If your iris are blooming in colors different than you expect it is more likely that a more vigorous variety has taken over.

My irises look healthy and produced stems, but the buds never opened. What happened?

Your irises are growing very quickly in the spring. This new growth is very tender. A cold night can abort the growth of the bloom buds.

My iris leaves are wrinkled up. Why?

Sometimes an iris fan will have stunted growth and foliage that appear like corrugated cardboard. This is called “pineappling.” The exact cause of this is not known, but the plant will not be lost. It is not a contagious disease. It is probably due to weather conditions.

Can I pot my iris?

Irises can be successfully grown in pots. First, select a pot that is roomy. Make sure your pot and soil mix drain well. Leave the top of the rhizome exposed and water only when the top two inches of soil are dry.

BACK