How to Balance pH for Dianella (Dianella spp.)

Dianella, also known as flax lily or blue flax lily, is a popular ornamental plant valued for its striking foliage and delicate blue flowers. To ensure optimal growth and health of your Dianella plants, it is crucial to maintain the proper soil pH level. In this comprehensive guide, we will walk you through the steps to balance the pH for Dianella (Dianella spp.).

What Is the Ideal pH Range for Dianella (Dianella spp.)?

Dianella plants thrive in slightly acidic soil with a pH range of 6.0 to 6.5. This pH range allows the plants to efficiently absorb nutrients from the soil, promoting healthy growth and vibrant foliage.

How to Test Soil pH for Dianella (Dianella spp.)

Dianella (Dianella spp.)

Before making any adjustments to your soil pH, it is essential to determine the current pH level. You can easily test your soil pH using the following methods:

  1. Home Testing Kit: Purchase a soil pH testing kit from your local garden center or online retailer. Follow the instructions provided in the kit to collect a soil sample and perform the test.

  2. Extension Service: Contact your local cooperative extension service and inquire about their soil testing services. They may provide soil testing kits or accept soil samples for analysis.

How to Adjust Soil pH for Dianella (Dianella spp.)

Once you have determined the current pH level of your soil, you can take the necessary steps to adjust it to the optimal range for Dianella plants.

Lowering Soil pH

If your soil test indicates a pH higher than 6.5, you can lower it by incorporating the following amendments:

  • Elemental Sulfur: Apply elemental sulfur to the soil at a rate of 1 pound per 100 square feet for every point you want to lower the pH. For example, if your pH is 7.5 and you want to bring it down to 6.5, apply 5 pounds of elemental sulfur per 100 square feet.

  • Aluminum Sulfate: Alternatively, you can use aluminum sulfate to lower the soil pH. Apply it at a rate of 5 pounds per 100 square feet for every point you want to lower the pH.

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Mix the amendment thoroughly into the soil and water it well. Wait for four to six weeks before retesting the soil pH, as it takes time for the sulfur to react with the soil.

Raising Soil pH

If your soil pH is below 6.0, you can raise it by adding the following amendments:

  • Agricultural Limestone: Apply agricultural limestone to the soil at a rate of 5 pounds per 100 square feet for every point you want to raise the pH.

  • Dolomitic Limestone: Dolomitic limestone can also be used to raise soil pH. Apply it at the same rate as agricultural limestone.

Incorporate the limestone into the soil and water it thoroughly. Wait for six to eight weeks before retesting the soil pH to allow the limestone to take effect.

How to Care for Dianella (Dianella spp.) After pH Adjustment

Dianella (Dianella spp.) 2

After adjusting the soil pH, it is important to provide proper care to your Dianella plants to ensure their continued health and growth.


  • Newly Planted Dianella: During the first two weeks after planting, thoroughly water the root balls and surrounding soil to establish the plants.

  • Established Dianella: Adjust your watering schedule based on the diameter of the plant’s trunks or canes. Refer to the UF/IFAS Extension guidelines for specific watering recommendations.

Organic Matter

  • Annual Application: Each spring, before the rainy season, apply a layer of organic matter such as compost or well-rotted manure around established Dianella plants. This helps improve soil structure, drainage, and nutrient balance.

How Long Does pH Adjustment Take for Dianella (Dianella spp.)?

The duration of pH adjustment depends on the amendment used and the initial pH level of your soil. Generally, it takes four to six weeks for sulfur amendments to lower the pH and six to eight weeks for limestone amendments to raise the pH. It is recommended to retest the soil pH after the specified time to ensure the desired pH range has been achieved.

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What Temperature and Watering Conditions Are Ideal for Dianella (Dianella spp.)?

Dianella plants prefer temperatures between 60°F to 80°F (15°C to 27°C). They are relatively drought-tolerant once established but benefit from regular watering during dry periods. Water deeply and allow the soil to dry out slightly between watering sessions to prevent waterlogging.

Home Remedies for Adjusting Soil pH for Dianella (Dianella spp.)

In addition to commercial amendments, you can use the following home remedies to adjust soil pH for Dianella plants:

  • Coffee Grounds: Sprinkle used coffee grounds around your Dianella plants to slightly lower the soil pH. Use them in moderation, as excessive amounts can lead to nutrient imbalances.

  • Wood Ash: Apply wood ash to the soil to raise the pH. Use it sparingly, as it can also alter the soil’s nutrient composition.

Remember, it is always best to rely on soil tests and use commercial amendments for more precise pH adjustments.


Balancing the soil pH for Dianella (Dianella spp.) is crucial for their optimal growth and health. By following the steps outlined in this guide, you can effectively test your soil pH, make necessary adjustments using appropriate amendments, and provide proper care to your Dianella plants. With the right pH level and growing conditions, your Dianella plants will thrive, rewarding you with their stunning foliage and delicate blue flowers.

1. Phacelia – ScienceDirect
2. Florida-Friendly Landscaping™ Guide – UF/IFAS Extension
3. Florida-Friendly Landscaping Guide – City of Pembroke Pines