Yellow iris leaves are an indication that your plant is stressed because of different reasons. This is a signal that your plant needs immediate attention. However, don’t worry because this is a common problem that growers face most of the time.Yellow Iris Leaves

In this article, we cover the easiest methods to treat and bring your plant back to its vigorous health more than before. We’re excited to help you out, let’s begin!

Why Are Your Irises’s Leaves Yellow? 7 Reasons

Your iris’ leaves are yellow for seven main reasons. Overwatering, underwatering, wrong soil pH, lack of or too much fertilizer, root rot, pests and diseases, and incorrect lighting exposure are the common reasons why yellow iris leaves occur in your iris pseudacorus.

– Overwatering and Underwatering

Overwatering iris pseudacorus can cause significant damage to its rhizomes and result in rot. The effects will eventually cause your plant to exhibit yellowing and browning leaves. This usually occurs when you are watering the plant too much within a short period of time. Overwatering can also result in sunburn of the roots, which turns the leaves brown and causes them to fall off.

Underwatering is another common reason for yellow iris leaves and has the same effect on the plant as overwatering. Lack of water for a long period of time will also result in leaves turning yellow and eventually withering and falling off as the plant cannot support its leaves, flowers, and thriving foliage.Causes of Yellow Iris Leaves

– Root Rot

This disease is a result of overwatering. This problem occurs when there is too much moisture in the soil. Your plant will consume all the water in the soil, which will eventually evaporate into the leaves, resulting in yellowing. This is the reason why you should keep the soil moist and avoid overwatering and consequently keeping the soil wet.

Bacteria, such as Erwinia carotovora, can also cause the rotting of roots in iris plants. This bacterium enters through broken skin in the rhizomes either when you nip the rhizomes by accident while pruning the plant or by the actions of a pest, enabling the bacterium to make its way inside the plant.

– Fertilization Issue

Adding fertilizers can be beneficial for your plant. However, giving too much or the wrong kind of fertilizer will also cause significant damage, such as the yellowing of the leaves and eventual plant death. Lack of fertilizer, on the other hand, will cause nutrient deficiency for your iris, along with other issues, such as rhizome rotting.

– Incorrect Lighting

Irises thrive in full sun but are sensitive to too much light exposure. Too much light will cause your plant to become leggy and yellow. On the other hand, lack of sunlight can cause stunted growth, affect the blooms, and make the leaves wilt and turn yellow, especially during the growing season.Solving Yellow Iris Leaves

– Wrong Soil pH

Iris plants prefer neutral soil pH, and it can cause a lot of problems when the soil pH goes above their preference. Your plant roots will become weak, and this condition may also cause some diseases for your iris plant. Make sure your iris has the correct soil pH, which is neither too acidic nor too alkaline.

– Pests

Aphids, mealybugs, whiteflies, scales, and spider mites are the common pests that can infest your irises. These little insects affect the growth of your plant as they feed on the leaves by piercing into the leaf with their mouthparts and sucking the plant juices. This causes the rhizome to rot and affects the appearance of the lily leaves.

– Diseases

Irises can be affected by either bacterial or fungal diseases, which will all start in the soil. Bacterial disease is caused by an overgrowth of bacteria, whereas fungal disease is caused by an overgrowth of fungus. Make sure to look out for the telltale diseases, such as bacterial leaf blight, crown rot, ink spot, iris leaf spot, and botrytis, among others, so that you can treat them accordingly.

Another disease that might affect your plant is the iris scorch disease. Though its origin is unknown, this causes the plant to decline in health. One of the initial symptoms can be seen at the center leaf of the fan, which turns into a brownish-yellow color. The scorched appearance spreads throughout the other leaves, which resist when being pulled out.

How to Solve the Yellow Iris Leaves? 7 Methods

To solve yellow iris leaves there are seven methods to follow. You have ensured they are watered adequately. You should treat root rot, if there is, and fertilize correctly. Furthermore, they should have adequate light and the right pH. Finally, make sure to get rid of pests and treat diseases.

– Adequate Watering

If you think your plant is suffering because of overwatering, reduce the frequency to once a week and then increase it slowly depending on the weather condition. During the summer, water your plant either in the mornings or in the evenings, but do not water it at noon. Always let the top two inches of the soil dry out before watering your plant again to avoid waterlogging.

For underwatering issues, keep in mind not to let the soil dry out completely before watering your plant again. During the spring and summer, water your plant lightly. Water it regularly according to a set schedule. It is also good to remember that once your iris is established, it does not need much watering.

– Treat Root Rot

Identifying root rot immediately will give your plant a greater chance of survival, but once it is severely rotting, it might be impossible to save your plant from eventually dying. Carefully dig around your plant and inspect the rhizome, look for soft, mushy, and rotting parts, and cut them off using a sharp knife.

If less than half of the rhizome is affected, you can transplant your iris using fresh soil.Remedies for Yellow Iris Leaves

– Correct Fertilization

Encountering fertilization issues is very common among yellow flag growers. To avoid this, make sure you use the right kind of fertilizer for your plant, and keep in mind to apply a sufficient amount. Fertilize your plant twice a year. Do the first application during the spring, and the second should be done after the last flower has faded.

– Adequate Light

Allow your iris plant to receive an adequate amount of sunlight, with at least six to eight hours of full sun daily through the summer and spring seasons. If potted, you can move your plant around where it faces west or south.

– Adjust Soil the pH of the Soil

If the soil is too acidic, you can raise the pH level of the soil by adding lime, which can be purchased at any garden center. Alternatively, you can do it yourself at home by using baking soda and limestone. On the other hand, if the soil is too alkaline, fix it by adding sulfur to the soil. Remember to adjust and maintain the soil pH between 6.8 to 7.0.

– Get Rid of Pests

You can use insecticidal soap or insecticidal oil on your irises. Spray it around the leaves and stems of your plant, and stop watering it for a while after applying the insecticidal soap or insecticidal oil to avoid washing off the active ingredients in these products.Common Pests in Iris Plants

– Treat Diseases

To avoid the diseases we have mentioned above, remember to keep the soil moist and not wet. You can also apply fungicide on your plant to prevent these nuisances from occurring. Most of these diseases can be treated using fungicides containing chlorothalonil, mancozeb, and myclobutanil – read and follow the instructions written on the packaging carefully before applying it to your plant.


Yellow iris leaves are a common problem, but it is easy to treat as long as you identify where the issue is coming from and make the appropriate correction to resolve it. Here are the main takeaways to remember to prevent yellow iris leaves:

  • Yellow flag prefers moist but not wet soil.
  • Six to eight hours of full sun daily will result in healthy plant growth.
  • Having the right soil pH greatly affects your plant’s health.
  • Get rid of pests, and treat diseases immediately.
  • Apply the right fertilizer the right way.

Upon reading and applying the care guide and tips we have covered, your iris plant will overcome the yellowing of its leaves, and the irises bloom will appear profusely in no time.

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