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Why Are My Dianella Plant Leaves Turning Yellow?

Updated: April 29, 2022

Dianella is a genus of evergreen plants that are native to Australia and New Zealand. They are prized for their attractive foliage, which typically features long, narrow leaves in shades of green, blue, or variegated colors. However, if you notice that the leaves of your Dianella plant are turning yellow, it may be a sign of a problem. In this article, we will explore some of the common reasons why Dianella plant leaves turn yellow and what you can do about it.

Lack of Water

One of the most common reasons why Dianella plant leaves turn yellow is due to a lack of water. These plants prefer moist soil, and if they do not receive enough water, their leaves will begin to wilt and turn yellow. If you notice that your Dianella plant is drooping and the soil feels dry to the touch, it is time to water it. Be sure to water deeply, so that the entire root system gets wet.


On the other hand, overwatering can also cause Dianella plant leaves to turn yellow. If the soil is constantly wet or soggy, the roots may become damaged and unable to absorb nutrients properly. This can lead to yellowing leaves and even root rot. To avoid overwatering, wait until the top inch of soil is dry before watering again.

Soil pH

Dianella plants prefer slightly acidic soil with a pH between 5.5 and 6.5. If the soil is too alkaline or too acidic, it can affect the plant’s ability to absorb nutrients properly. This can lead to yellowing leaves as well as stunted growth. To test your soil’s pH level, you can use a soil testing kit or take a sample to your local garden center for analysis.

Nutrient Deficiency

Yellowing leaves can also be a sign of nutrient deficiency. Dianella plants require nitrogen, phosphorus, and potassium to grow properly. If any of these nutrients are lacking in the soil, the plant may begin to show signs of yellowing leaves. You can add a balanced fertilizer to the soil to correct this issue.

Pests and Diseases

Finally, yellowing leaves can also be a sign of pests or diseases. Spider mites, aphids, and mealybugs are common pests that can infest Dianella plants and cause yellowing leaves. Fungal diseases such as leaf spot and root rot can also cause yellowing leaves. To prevent and treat these issues, it is important to keep your plant healthy with proper watering and fertilization, as well as regular monitoring for pests and diseases.


Can I cut off the yellow leaves?

Yes, you can cut off the yellow leaves to improve the appearance of your plant. However, it is important to address the underlying issue that caused the leaves to turn yellow in the first place.

How often should I fertilize my Dianella plant?

Dianella plants should be fertilized once per month during the growing season (spring and summer). Use a balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium.

Should I prune my Dianella plant?

Yes, you can prune your Dianella plant to remove any dead or damaged foliage. Pruning can also help to promote new growth and improve the overall appearance of the plant.

In conclusion, yellowing leaves on your Dianella plant may be a sign of several issues including lack of water, overwatering, improper soil pH, nutrient deficiency, or pests and diseases. By addressing these underlying issues and maintaining proper care for your plant, you can help keep your Dianella looking healthy and vibrant.