Hydrangea Magic: Changing Bloom Colors

by Amanda

blue and pink hydrangea bloomsblue and pink hydrangea blooms

Hydrangeas: Color-changing Magic?

A common question we get from gardeners each year is: "Why are my blue Hydrangeas pink, or, Why are my pink Hydrangeas blue?" The answer is really quite simple (and no, it's not magic). The color of your Hydrangea blooms are directly linked to the PH levels of your soil.

Knowing this important information means you can easily (well, somewhat easily) change the color of your Hydrangea blooms! Alkaline soil produces pink blooms and acidic soil produces blue blooms. The first step in determining the PH of your soil is to do a soil PH test to determine the acidity of your soil.

Blue to Pink:

A test result below 7 means that your soil is acidic (blue blooms). To raise the PH of your soil (to turn blooms pink), try adding limestone – most packages will tell you how much to add to increase your PH to the correct levels.You can also try using a fertilizer with high levels of phosphorus in it. This helps keep the aluminum in your soil from entering the root system of your plant. If you can't seem to lower the acidity in your garden beds, consider planting in pots.

colorful hydrangea bouquetcolorful hydrangea bouquet
blue hydrangeablue hydrangea
pink and white hydrangeapink and white hydrangea

Pink to Blue:

A test result above 7 means that your soil is alkaline (pink blooms). To lower the pH of your soil (to turn blooms blue), you can add things such as sulfur, compost, pine needles, or pine bark. This will help to add some acidity to your soil. You can also try an organic fertilizer that is low in Phosphorus and high in Potassium.

  1. Annabelle Snowball Hydrangea

    Annabelle' Hydrangea is famous for its huge, snow-white blooms and excellent cold hardiness. This shorter variety grows 3 - 5 ft tall and flowers reliably, even after severe winters ...

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    Annabelle Snowball Hydrangea Snowball Hydrangea Annabelle Hydrangea arborescens Annabelle
    $19.98 Sale $9.99
    Per Plant - 3.5" Pot
    Annabelle' Hydrangea is famous for its huge, snow-white blooms and excellent cold hardiness. This shorter variety grows 3 - 5 ft tall and flowers reliably, even after severe winters and intentional pruning. Its enormous 10" blooms and ability to adapt to both cold and heat have made 'Annabelle' one of the most popular hydrangeas in the country. (Hydrangea arborescens)
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  2. Blue Hydrangea All Summer Beauty, Hydrangea macrophylla, Mophead Hydrangea

    'All Summer Beauty' Hydrangea is a compact, long-blooming mophead variety that produces big, bouncy flowers on 4 ft shrubs. Because it blooms on both new growth and old wood, flowers...

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    All Summer Beauty Mophead Hydrangea Mophead Hydrangea All Summer Beauty Hydrangea macrophylla All Summer Beauty
    $19.98 Sale $9.99
    Per Plant - 3.5" Pot
    'All Summer Beauty' Hydrangea is a compact, long-blooming mophead variety that produces big, bouncy flowers on 4 ft shrubs. Because it blooms on both new growth and old wood, flowers will form throughout the season, even after a harsh winter - which can be the undoing of other hydrangeas. Known for its bright blue blooms in acid soils, expect to see shades of pink and purple where the ground is more alkaline. (Hydrangea macrophylla)
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  3. Hydrangea, Oak Leaf Hydrangea Ruby Slippers

    'Ruby Slippers' Oak Leaf Hydrangea delivers oversized, cone-shaped blooms that arrive in light pink and deepen to a reddish-magenta as they age. A compact shrub, 'Ruby Slippers' is a...

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    Ruby Slippers Oak Leaf Hydrangea Oak Leaf Hydrangea Ruby Slippers Hydrangea quercifolia Ruby Slippers
    $29.98 Sale $22.49
    Per Plant - 3.5" Pot
    'Ruby Slippers' Oak Leaf Hydrangea delivers oversized, cone-shaped blooms that arrive in light pink and deepen to a reddish-magenta as they age. A compact shrub, 'Ruby Slippers' is a fine choice for small spaces and planting in containers, or training into a low hedge. Its lobed, oak-like leaves change to burgundy as fall appoaches, bringing another layer of vibrant color to the landscape. (Hydrangea quercifolia)
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  4. Mophead Hydrangea Everlasting Revolution PP22,260, Hydrangea macrophylla

    Everlasting® 'Revolution' Mophead Hydrangea delivers a medley of colorfully blended blooms to the summer garden. Expect to see varying shades of pink, purple and blue (depending on ...

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    Everlasting® Revolution Hydrangea Everlasting® Revolution Mophead Hydrangea Hydrangea macrophylla Everlasting® Revolution
    $29.98 Sale $22.49
    Per Plant - 3.5" Pot
    Everlasting® 'Revolution' Mophead Hydrangea delivers a medley of colorfully blended blooms to the summer garden. Expect to see varying shades of pink, purple and blue (depending on your soil type) flowerheads on this compact shrub, all highlighted with bright green accents. 'Revolution' is a heavy bloomer that was bred to produce extra-sturdy stems, making it an excellent choice for cut flowers. Container friendly. (Hydrangea macrophylla)
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The best success rate comes from gardeners who grow their Hydrangeas in containers, which allows for them to completely control the acidity of the soil with no outside factors.

Also note that it is easier to change a pink Hydrangea to blue than blue to pink. Other colors of Hydrangea cannot change colors with soil acidity.

What experience do you have changing the colors of your Hydrangeas? Please post in the comments below or on our Facebook Page.

Happy Gardening!

Interested in learning more about Hydrangeas?

Check out our easy-to-follow resources written by gardening experts

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