How to Balance pH for Tree Peonies

Maintaining the proper pH level is crucial for the healthy growth and vibrant blooms of tree peonies. This comprehensive guide will walk you through the steps to balance the pH of your soil, ensuring your tree peonies thrive.

Understanding the Ideal pH Range for Tree Peonies

Tree peonies prefer a slightly acidic to neutral soil pH, with an optimal range of 6.5 to 7.5. This pH range ensures the availability of essential nutrients and creates an environment that supports the plant’s overall health and vigor.

Identifying the Current Soil pH

tree peonyImage source: Pixabay

Before you can adjust the pH, you need to determine the current pH level of your soil. You can do this by using a soil test kit or by sending a soil sample to a local extension service or laboratory for analysis. This will provide you with the baseline information you need to make the necessary adjustments.

Adjusting the Soil pH

If your soil test reveals a pH outside the ideal range for tree peonies, you’ll need to take action to bring it into the optimal range.

Increasing Soil pH (Making it More Alkaline)

If your soil is too acidic, you’ll need to add a pH-raising amendment, such as:

  1. Agricultural Lime: Apply lime at a rate of 2-4 pounds per 100 square feet of soil. Incorporate it into the top 6-8 inches of soil.
  2. Wood Ash: Sprinkle a thin layer of wood ash (1/4 to 1/2 inch) over the soil and mix it in.
  3. Dolomitic Lime: This type of lime also adds magnesium to the soil, which can be beneficial for tree peonies. Apply at a rate of 2-4 pounds per 100 square feet.
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Decreasing Soil pH (Making it More Acidic)

If your soil is too alkaline, you can lower the pH by adding acidic amendments, such as:

  1. Sulfur: Apply sulfur at a rate of 1-2 pounds per 100 square feet of soil. Mix it into the top 6-8 inches.
  2. Peat Moss: Incorporate peat moss into the soil at a rate of 2-4 cubic feet per 100 square feet.
  3. Aluminum Sulfate: Apply aluminum sulfate at a rate of 1-2 pounds per 100 square feet of soil.

It’s important to note that adjusting the soil pH can take several months, so be patient and monitor the progress. Retest the soil after a few months to ensure the pH is within the desired range.

Maintaining the Proper pH

tree peony 2Image source: Pixabay

To maintain the ideal pH for your tree peonies, you’ll need to periodically retest the soil and make any necessary adjustments. As a general guideline, it’s recommended to test the soil and make any pH corrections annually, preferably in the fall or early spring.

Complementary Soil Amendments

In addition to adjusting the pH, you can also improve the overall health and fertility of your tree peony’s soil by incorporating the following amendments:

  1. Compost: Add 2-4 inches of well-decomposed compost to the soil and mix it in.
  2. Bone Meal: Apply bone meal at a rate of 1-2 cups per plant to provide phosphorus and calcium.
  3. Greensand: Sprinkle greensand around the base of the plant to supply iron and potassium.

Remember to always follow the manufacturer’s instructions for the specific products you’re using, as the recommended application rates may vary.

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Watering and Temperature Considerations

Tree peonies thrive in well-drained soil and prefer consistent moisture, but they can be sensitive to overwatering. Water the plants deeply, but allow the soil to partially dry out between waterings. Aim to keep the soil moist, but not waterlogged.

Regarding temperature, tree peonies prefer cool, mild conditions. Avoid planting them in areas with extreme heat or cold, as this can stress the plants and impact their growth and flowering.


Balancing the pH of your soil is a crucial step in ensuring the healthy growth and vibrant blooms of your tree peonies. By following the guidelines outlined in this article, you can create the ideal growing conditions for your tree peonies to thrive. Remember to regularly test your soil, make any necessary adjustments, and provide the right growing conditions for your plants to reach their full potential.


  • Peony Planting: Site Selection and Preparation – Cricket Hill Garden
  • Growing & Planting Woody (Tree) Peonies – American Peony Society
  • Spring Fertilization of Peonies – Cricket Hill Garden