Hydrangea

How to Turn Hydrangea Flowers Blue (video)

Hydrangeas are easy-to-grow perennials that will bloom beautifully year after year with little to no effort! Hydrangea flowers can range from sapphire blue to pink. Here I will show you step by step, how to turn your hydrangea flowers blue. Below you can also watch my video on how to turn hydrangea flower blue.

How to Turn Hydrangea Flowers Blue video

1. Make Sure you Have the Correct Hydrangea Variety

Not all hydrangea varieties turn blue. You need to make sure you have the bigleaf hydrangea variety. Bigleaf hydrangea flowers can turn blue, purple, or pink depending on the soil pH. Other hydrangea varieties such as the Anabelle hydrangea have white flowers. These flowers will not turn blue or pink. Make sure you have the bigleaf hydrangea variety. In the garden center, look for Bigleaf hydrangeas such as Nikko Blue Hydrangea, Endless Summer Original Hydrangea, Penny Mac Hydrangea and Endless Summer Twist and Shout Hydrangea

2. Measure the Soil pH

There are many ways to measure soil pH. The easiest way is to use a soil tester or soil pH strips to measure the pH. If you don’t have a soil tester at home, you can use vinegar and baking soda to measure the soil pH.

First, collect garden soil, wet it, and then add vinegar to your garden soil sample. If it starts to bubble, then your soil is reacting to the vinegar which means it is alkaline.

Alternatively, when you add baking soda to your wet garden soil. If it starts to bubble, your soil is reacting to the baking soda which means your soil is acidic. If there is no bubbling with vinegar or baking soda, then you have neutral soil. 

You can check out my post on How to Measure Soil pH without a soil test kit. You can also watch my video on how to measure soil pH without a soil test kit.

Another way to determine your soil pH is to look at your hydrangea plant. If your hydrangea flowers are pink, then you have alkaline soil. If your hydrangea flowers are purple, you have neutral soil and if your hydrangea flowers are blue, your soil is acidic. 

3. Soil pH for Blue Hydrangea Flowers

If you want blue hydrangea flowers, you need to have acidic soil of pH 5.5 or lower. 

4. Soil pH for Pink Hydrangea Flowers

If you want pink hydrangea flowers, you need to have alkaline soil of pH 6.5 or higher.

5. Soil pH for Purple Hydrangea Flowers

For purple flowers or a mix of blue and pink flowers on the same plant, you need to have a close to neutral soil pH of 5.5 to 6.5.

6. How to Make your Hydrangea Flowers turn Blue

To make hydrangea flowers turn blue, you need to make your soil acidic. You can do this by adding Potassium Aluminum Sulfate but the easiest is to add pre-packaged soil acidifiers that are found in garden centers. Know that it takes time for your hydrangea flowers to turn blue. You will need to apply a few rounds of soil acidifiers for your hydrangea flowers to turn blue. Also, if you already have pink hydrangea flowers on your hydrangea plant, it will not turn blue since the flowers have already bloomed pink. You will have to wait until next year for blue hydrangea flowers.

7. How to Make your Hydrangea Flowers turn Pink

To make hydrangea flowers turn pink, you need to increase your soil alkalinity. You can do this by adding garden lime which you can find at your local garden center.

It takes time for your Hydrangea flowers to turn blue, be patient and adjust your soil pH as needed.  

You May Also be Interested in these Hydrangea Care Tips

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Beginner’s Guide: How to Care for your Hydrangea (video)

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