Whether you prefer the cool blue hydrangea flowers or the warm pink blooms, with the right soil pH, your hydrangeas can change color and beautify your garden for years to come.
Hydrangeas are cherished for their stunning blooms, which can range in color from blue to pink and even purple. One of the unique features of certain hydrangea varieties, particularly Hydrangea macrophylla (Bigleaf Hydrangea), is their ability to change color based on the soil’s pH levels. This guide will provide you with detailed information on how to manipulate the soil to achieve your desired hydrangea color, along with essential care tips to keep your plants healthy and vibrant.
The color of hydrangea flowers is primarily influenced by the availability of aluminum ions in the soil. Here’s how it works:
Acidic Soil (pH below 6.0): In acidic conditions, aluminum ions are more readily absorbed by the plant roots, resulting in blue flowers.
Neutral to Alkaline Soil (pH above 6.0): In neutral or alkaline conditions, aluminum becomes less available, leading to pink flowers.
Not all hydrangea varieties will react the same way to soil amendments. Here are the hydrangea plants to consider:
This hydrangea species is a cherished garden choice. This deciduous shrub features a rounded growth habit, showcasing large, lush leaves and long-lasting summer blooms. It is categorized into two main types: Mophead Hydrangeas, characterized by their large, vibrant flower heads, and Lacecap Hydrangeas, which display flat clusters of radiant sterile florets encircling small, fertile ones.
This graceful deciduous shrub has a rounded growth habit and showcases delicate lace-cap flowers in flattened clusters from early to late summer. While reminiscent of the Bigleaf Hydrangea, it exhibits a more refined appearance and features smaller flowers and leaves. The elegant blossoms of some cultivars bloom in abundance and possess the enchanting ability to change color three to four times throughout the season, adding dynamic beauty to any garden.
Please note that the color of white hydrangeas is not influenced by soil pH; their flowers remain white and cannot be changed.
Kardinal Violet Hydrangea – Hydrangea macrophylla or Bigleaf Hydrangea
Before making any adjustments to your hydrangea’s environment, it’s crucial to determine the current pH level of your soil. Here’s how to test it:
If your soil is more alkaline and you desire blue blooms, follow these steps:
Add Aluminum Sulfate: This amendment lowers pH and provides aluminum ions to the plants. Apply according to package instructions; typically, a rate of 1 tablespoon per foot of plant height is effective.
Use Elemental Sulfur: This is a gradual method that may take several months to show results. Incorporate it into the soil in the spring or fall, mixing it well into the topsoil.
Mulching: Use mulch made from pine needles, shredded oak leaves, or other acidic materials to help maintain lower pH levels. This also protects the roots and retains soil moisture.
Nikko Blue Hydrangea – Hydrangea macrophylla or Bigleaf Hydrangea
To achieve pink blooms, you’ll need to raise the soil pH. Here’s how:
Add Lime: Incorporate agricultural lime or dolomitic lime into the soil according to the instructions on the package. This will help raise the pH and reduce the availability of aluminum ions.
Test Soil pH Regularly: After making adjustments, retest the soil pH every few months to ensure you are moving towards your desired level.
Peppermint Hydrangea – Hydrangea macrophylla or Bigleaf Hydrangea
Keep in mind that altering hydrangea color is not instantaneous. Expect to see results within weeks to months. Changing blue flowers to pink is generally easier than the reverse.
Additionally, it’s advisable to wait until the plant is about two years old to ensure it can handle the stress of any adjustments.
Now that your hydrangeas are showcasing stunning blue, pink, or purple blooms, consider drying them to preserve their beauty for crafts, floral arrangements, or home decor. This way, you can enjoy their vibrant colors long after the blooming season has ended.
Hydrangeas are beloved for their beautiful blooms, but sometimes gardeners encounter issues that prevent these flowers from reaching their full potential. Here are some common problems related to hydrangea blooms, along with their causes and solutions:
Hydrangeas do not produce flowers or have very few blooms. Possible causes:
Flowers are small, lack vibrancy, or appear wilted. Possible causes:
Flowers are turning brown or losing their vibrant color.Possible causes:
Possible Causes:
Hydrangea flowers are changing color unexpectedly. Changes in soil acidity can lead to color shifts. For instance, blue flowers may turn pink if the soil becomes less acidic.
Test your soil pH regularly, especially after adding amendments, and adjust accordingly to maintain your desired color.
Blooms fade quickly after opening. Possible Causes:
All Summer Beauty – Hydrangea macrophylla or Bigleaf Hydrangea
Yes, coffee grounds can help make soil more acidic, which can contribute to turning hydrangeas blue. When added to the soil, coffee grounds release nitrogen and may slightly lower the pH, promoting blue coloration in varieties like Hydrangea macrophylla.
Vinegar, particularly white vinegar or apple cider vinegar, can lower soil pH when applied to the soil, making it more acidic. This can encourage blue blooms in hydrangeas. However, it’s important to use it sparingly, as excessive acidity can harm the plants.
Yes, apple cider vinegar can help turn hydrangeas blue by lowering the soil pH when applied. Like white vinegar, it should be used carefully to avoid excessive acidity that could harm the plant.
Eggshells are primarily made of calcium carbonate, which can raise soil pH and make it more alkaline. As a result, they may contribute to pink blooms rather than blue. If your goal is to achieve blue flowers, you should avoid using eggshells in the soil.
The speed at which you can turn hydrangeas blue depends on several factors, including the current soil pH and the methods used. Typically, changes can be observed within a few weeks to a couple of months after applying acidic amendments. However, for significant color changes, especially if starting from a neutral or alkaline base, it may take a full growing season or longer for optimal results.
Hardiness |
3 - 9 |
---|---|
Heat Zones |
1 - 9 |
Plant Type | Shrubs |
Plant Family | Hydrangeaceae |
Genus | Hydrangea |
Exposure | Full Sun, Partial Sun |
Season of Interest | Spring (Late), Summer (Early, Mid, Late), Fall |
Maintenance | Low |
Water Needs | Average |
Soil Type | Clay, Loam, Sand |
Soil pH | Acid, Alkaline, Neutral |
Soil Drainage | Moist but Well-Drained |
Characteristics | Dried Arrangements, Cut Flowers, Showy |
Attracts | Butterflies, Hummingbirds |
Landscaping Ideas | Patio And Containers, Hedges And Screens, Beds And Borders |
Hardiness |
3 - 9 |
---|---|
Heat Zones |
1 - 9 |
Plant Type | Shrubs |
Plant Family | Hydrangeaceae |
Genus | Hydrangea |
Exposure | Full Sun, Partial Sun |
Season of Interest | Spring (Late), Summer (Early, Mid, Late), Fall |
Maintenance | Low |
Water Needs | Average |
Soil Type | Clay, Loam, Sand |
Soil pH | Acid, Alkaline, Neutral |
Soil Drainage | Moist but Well-Drained |
Characteristics | Dried Arrangements, Cut Flowers, Showy |
Attracts | Butterflies, Hummingbirds |
Landscaping Ideas | Patio And Containers, Hedges And Screens, Beds And Borders |
Create a membership account to save your garden designs and to view them on any device.
Becoming a contributing member of Gardenia is easy and can be done in just a few minutes. If you provide us with your name, email address and the payment of a modest $25 annual membership fee, you will become a full member, enabling you to design and save up to 25 of your garden design ideas.
Join now and start creating your dream garden!
Create a membership account to save your garden designs and to view them on any device.
Becoming a contributing member of Gardenia is easy and can be done in just a few minutes. If you provide us with your name, email address and the payment of a modest $25 annual membership fee, you will become a full member, enabling you to design and save up to 25 of your garden design ideas.
Join now and start creating your dream garden!