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How to Change Hydrangea Color to Blue from Pink

Dean Darin
Written by Dean Darin
Updated May 9, 2016
pink and purple hydrangea flower heads
You can change the color of most hydrangeas (other than white varieties) from pink to blue by adjusting the soil’s pH level, or acidity.

Meranda Adams

Achieving the perfect blue hydrangea flower is possible! You can change the color of most hydrangeas from pink to blue or purple by adjusting soil acidity.

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A flower garden filled with big, bright blue flowers is every grower’s dream. This elusive blue flower is quite hard to come by, though. Meet the hydrangea, a truly magical flower with the power to transform from pink or purple to blue hydrangea flowers with one simple trick.

The secret is in the soil.

Soil acidity changes hydrangea color

Most hydrangeas, except white varieties, change color based on the pH, or acidity levels, of the soil. By adjusting the soil’s pH level, you can get the shade of blue you’ve been dreaming of.

Transforming your pink hydrangeas to the perfect blue hue does take time. For large, established hydrangeas, the color conversion can take months. But, it’s definitely worth the wait.

While it may take time, creating gorgeous blue hydrangeas is easy. Simply amend your soil with Espoma Organic Soil Acidifier.

Other soil acidifiers contain Aluminum Sulfate, which can be harsh on plants. To keep your garden safe for pets, people and the planet, lower soil pH levels organically.

Consider location before planting blue hydrangeas

Increase your chances of success by checking these two factors before turning your hydrangeas blue:

1. Find out if the other plants near your hydrangeas like acidic soil, too.

2. Ensure hydrangeas are planted away from concrete paths or patios. Concrete often contains lime, which can leech into the soil and make it tough to amend.

Once you’ve checked your surroundings, you’re ready to turn pink hydrangeas blue.

How to make plant soil more acidic

For new hydrangeas, use 1 1/4 cups of organic soil acidifier for the brightest blues.

To transform established hydrangeas into blue beauties, apply 2 1/2 cups of organic soil acidifier to the soil.

Spread soil acidifier evenly around the hydrangea, out to its drip line or the widest reaching branches. Then, water hydrangeas well. Repeat every 60 days until hydrangeas reach the ideal blue hue. Keep an eye on your soil’s pH level by performing a simple, DIY soil test.

• For deep blue blooms, aim for a soil pH of 4.5.• For a muted blue, you want the soil pH to be 5.• For violet-blue hydrangea blossoms, your soil pH should be 5.5.

Craving hydrangeas with super-saturated blue color? Feed hydrangeas regularly with Espoma Holly-tone. Holly-tone fertilizer for acid loving plants also lowers your soil’s pH. Plus, regularly feeding your hydrangea leads to bigger, better blooms — and who doesn’t want that?

As of May 8, 2016, this service provider was highly rated on Angie's List. Ratings are subject to change based on consumer feedback, so check Angie's List for the most up-to-date reviews. The views expressed by this author do not necessarily reflect those of Angie's List. 

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