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Why are My Irises not Blooming? Revealed!

There are about 300+ species of Irises in the world, which bloom with six-petaled flowers.

Irises are one of the easiest and most beautiful plants to grow, but it can be a bit disheartening when you put in all the effort, and for some reason, they end up not Blooming.

Generally, there are many reasons behind Iris not blooming, such as lack of sunlight, improper watering, overcrowding of the plant, poor rhizomes, and unhealthy soil. So you need to provide optimum care requirements to make Irises bloom. 

An Iris plant does not bloom in the shade.

Last year we had a group of Irises that resisted blooming, so we were compelled to ornate only with flat leaves arranged in a fan shape. 

As soon as the blooming period ended, we fixed the sterilized Irises. So, if you Irises have suffered a similar condition like this, do not move ahead without reading this article. 

How Often Do Irises Bloom?

Generally, Irises are perennials that bloom from late spring to early summer.

However, some Siberian and Japanese Irises produce flowers from mid-spring to early summer, whereas Southern blue flags witness blossoms in early summer.

These perennials start blooming in the month ranging from March to the end of June.

However, there are other types of Irises that rebloom during late summer and fall.

For instance, Dwarf Irises have flowers early in the spring, whereas Dutch Irises bloom during May and Bearded Irises produce flowers at the end of May and throughout June.

Most of the Iris varieties have flowers a couple of times per year in USDA Zones 5 to 6, but the blooming time varies from one species to another.

Once Irises bloom, their blossoms last for about 1-2 weeks at max. It can be longer if the conditions are perfect but shorter if the weather is bad.

Iris plants bloom well under full sunlight.

Some varieties of Irises bloom once in two years, and some bloom every year.

If you want to have an Iris garden that blooms throughout the year, I suggest you plant different varieties of Irises that bloom at different times of the year.

With that, you can have a year-round Iris blossom in your garden.

Why are My Irises not Blooming?

If the Iris blooms one year and escapes the next year, this might be the nature of the variety. However, many Irises lack blossoms due to unfavored care treatments. 

So, let you know in detail why your Irises lack flowers in the blooming period. 

1. Poor Rhizhomes or Bulbs

The rhizomes of Irises take time to get accustomed to the ground, so you may not witness the plants having flowers in the first year of plantation. 

With that said, the most obvious reason that your Irises are not blooming is that they have poor rhizomes or bulbs, depending on which species you are growing.

This process is also called soft rot in Irises as their leaves grow softer and softer as time passes while the rhizomes become mushier.

Rhizomes can also rot and cause your Iris to die or stop blooming if you do not care for it properly.

Iris Rhizome
Iris rhizomes can get together in clusters and get very complex.

If your Iris’s rhizome or the blub is under-formed and small, it can harm the blooming ability and entire plant. 

It will also result in your Iris plant becoming limp and stunted.


  • You need to dig out each infected rhizome and check it carefully.
  • After digging them out, use a sharp, sterilized knife and cut them off from the part they have turned mushier and started rotting.

2. Insufficient Light

The next cause your Irises might not be blooming is the lack of fulfillment of its lighting necessities.

Irises need full sun to bloom, and if you have kept your Iris in a shady or damp place, no wonder it is not growing. Even if it survives the shade somehow, the plant will fail to deliver the flowers. 

Irises require at least six hours of direct sunlight to bloom properly.

Iris plants do not bloom if the sunlight is filtered or below 6 hours a day.

This is because Irises need a ton of energy to bloom. 


  • Plant your Irises on the brightest part of your garden where they can receive the maximum amount of sunlight.
  • While placing your Iris, makes sure other plants or trees are not shading its direct sunlight.
  • If you live in the frosty zone, use the grow lights for at least 12 hours. 

3. Underwatering or Overwatering

The next problem that might be causing your Iris not to bloom is either over or underwatering.

Though Irises are drought resistant, they prefer to be moist around the roots but not on their stems. They require well-draining soil all year round as it helps their roots become stable and grow.

Overwatering your Irises can cause its roots to become mushy, which can cause root rot.

Damp soil can cause root rot and restrict Iris blooming.

On the other hand, underwatering Iris invites water stress restricting soil from becoming wet enough to supply the nutrients. If the soil gets compacted, the required foods do not reach all parts of the plant. 


  • Use the soak-and-dry technique to ensure proper watering. 
  • Wait until the top 2 inches of its soil is dry.
  • Water Irises in the morning so that moisture will be available to them during the heat of the day.
  • Depending on the weather, you can extend the days between watering as Irises does not need much water during the winter.

4. Improper Planting in the Soil

The common mistake many people make while planting their Irises is planting them too deep in the soil.

Only a few rhizomes can scratch the surface of the soil due to this. 

The rhizomes of the Iris plant require air circulation and sunlight to survive, and burying the rhizomes deep in the soil affects Iris’s growth.

Thus, rhizomes also face issues if they are buried deep in the ground. Though Irises can sprout foliage, they will fail to showcase the flowers. 


  • Plant the Irises or rhizomes an inch deep. The plants feel suffocation deeper than two inches in the ground. 
  • If plants are buried deep, make sure to dig them out and expose them to the upper part of the soil.
  • Plant the rhizomes or bulbs near the soil surface, and if possible, keep them with the tops at or slightly below the surface level.

5. Not Enough Space

Irises require a good area to spread out, grow and bloom while forming their roots. But if you have planted your Iris plants too close to each other, that might cause them stress.

Iris tends to overcrowd themselves with the passing years since their rhizomes multiply.

Iris Rhizomes
If the rhizomes get too crowded, you need to divide them and plant the divisions.

As the clumps grow old, it gets big and causes individual rhizomes to fight for resources.

If you notice the Iris in the pot has stopped blooming, you must learn that the plant is overcrowded. 


  • Plant your Irises around the distance of 12-24 inches between them.
  • Dig up the rhizome or bulb and divide it if there are crowded Irises.
  • Trim the iris’ foliage to approximately 6 inches in height, waive the soil gently and break the young bulbs with fingers. 
  • Now replant the divided Irises and moisten the soil to allow them to establish. 

6. Poor Soil 

Irises require well-drained soil rich in nutrients and a bit on the acidic side of the spectrum.

A soil with pH of 6.5-6.8 is best for Irises to bloom.

Irises are heavy feeders and may need an additional dose in the blooming period. You will not see them bloom if you forget to feed the Irises.

Iris plant does not bloom if the soil lacks phosphorus.

Besides, Irises fail to flower if there is excess nitrogen or not enough phosphorus in the soil. Also, overfeeding Irises with animal manure or fertilizer rich in nitrogen can cause the plant to be sterile.


  • Use ground melon to make the soil slightly acidic. 
  • Apply the early spring colloidal phosphate or bone meal to Irises to develop blooms.

Tips for Making Irises Bloom

Having the Iris blooms in the house is a wonderful time, but you need to make some effort for it. Here are some quick tips that help you make your Iris bloom and care for the plant. 

  • Avail the Irises in direct sunlight for about 6-8 hours a day.
  • Maintain the soil pH around 6.8 for Irises
  • Don’t water it too frequently and maintain around 7-10 days gap between watering.
  • Use low nitrogen fertilizers with a ratio of 5-10-10 in early spring, about 6 to 8 weeks before bloom. And if possible, use organic fertilizer. 
Iris plants bloom well outdoors.
  • You need to maintain the ideal temperature between 40° and 50°F. 
  • Keeping the relative humidity level between 40% and 50% will be great. 
  • If found pests, including hoplia beetle and leaf-chewing caterpillars, dispose of them in soapy water. 
  • Some diseases of Iris are fusarium wilt, bacterial leaf blight, botrytis rhizome rot, and crown rot. So, you need to apply fungicide once every 7-10-days if the diseases are severe.


Do not make haste to condemn that Irises suffer some serious issues as the plants may not be old enough to bloom flowers. 

For example, the Irises grown from seeds need at least two years to yield blossoms.

However, if the Irises have grown old enough and still there is no sign of blooming, you must seek the causes. 

If your Iris is old enough, you may need to learn about transplanting Iris

Happy Gardening!

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