Southern Living Plants Logo
  • About Us
    • History Of The Collection
    • Events
    • Brochure
    • Testimonials
    • Botanical Gardens
    • Why Choose Plants from Southern Living® Plant Collection?
  • The Plants
    • Shrubs
    • Trees
    • Berry Plants & Fruit Trees
    • Annuals and Perennials
    • Groundcovers/Grasses
    • Tropicals
    • Vines
    • New Introductions
  • Where to Buy
    • Find a Retailer
    • Online Retailers
    • Local Landscapers
  • In the Garden
    • Plan Your Garden
    • Inspiration & Projects
    • Planting & Care
  • Connect With Us
    • Like Us
    • Pinterest
    • #SLPlants
    • Youtube
    • Request Newsletter
Menu
  • About Us
    • History Of The Collection
    • Events
    • Brochure
    • Testimonials
    • Botanical Gardens
    • Why Choose Plants from Southern Living® Plant Collection?
  • The Plants
    • Shrubs
    • Trees
    • Berry Plants & Fruit Trees
    • Annuals and Perennials
    • Groundcovers/Grasses
    • Tropicals
    • Vines
    • New Introductions
  • Where to Buy
    • Find a Retailer
    • Online Retailers
    • Local Landscapers
  • In the Garden
    • Plan Your Garden
    • Inspiration & Projects
    • Planting & Care
  • Connect With Us
    • Like Us
    • Pinterest
    • #SLPlants
    • Youtube
    • Request Newsletter
Search
Close
4 large and blue Big Daddy Hydrangea

Hydrangeas Without the Blues

  1. Home
  2. Hydrangeas Without the Blues
  • By Kim Toscano
  • April 17, 2020
How to manage blossom color

Hydrangeas are beloved for their bold blossoms and vivid color. But for some gardeners, the plants never seem to bloom as intensely as they did at the garden center.

What should be bright, blue blossoms are dull and muted, or worse, the flowers are all pink. If your hydrangeas have yet to get the blues, don’t despair – this common problem is related to soil nutrition and can easily be corrected.

Controlling Color 101

Interestingly, flower color in bigleaf hydrangea, Hydrangea macrophylla, is strongly influenced by soil pH and its resulting effect on the availability of aluminum in the soil. A blue hydrangea needs aluminum in order to produce the rich, blue color. The more aluminum a bigleaf hydrangea can take from the soil, the more intensely blue the flower color will become. In contrast, less aluminum available to the plant results in pinker flowers. Genetics of the cultivar also influence the shade of blue or pink found in a hydrangea flower.

So what does this have to do with soil pH? Whether the hydrangea is growing in a container or garden soil, pH and the presence of other nutrients will determine whether aluminum is available to the plant. Aluminum is more readily available for uptake by plants in soils with low pH (acidic) and less available in higher pH soils (alkaline). As such, in acidic soils hydrangea bloom color is blue, while alkaline soils create pink blossoms.

How to Change from Pink to Blue

Gardeners can alter soil pH and therefore flower color, with the addition of powdered or pelletized sulfur to the soil. Before amending soil, conduct a soil test to determine the present soil conditions, and therefore, how much sulfur is required to achieve the desired change in pH. For blue flowers, aim for a soil pH between 5.0 and 5.5. Soil tests will also determine if aluminum is present in the soil at adequate levels. Conduct soil tests every two years to monitor soil pH and aluminum.

Ideally, gardeners amend soil pH before planting, but if you are working around existing plants, be sure to work the sulfur into the soil. Altering soil pH takes several months, so do not expect to see results immediately. Amending soil in autumn will impact hydrangea flower color the following summer. Once soil has been amended, annual fertilization with aluminum sulfate will help maintain soil pH and encourage deep blue flowering. You may also find specialty fertilizers for hydrangeas that will serve this purpose.

A Quick Fix

Many of the hydrangeas on display in garden centers have benefited from an application of aluminum sulfate during bud development. For individual plants, you can ensure blue blossoms for the current season by applying a liquid soil drench around the plant as flower buds are forming in mid spring. Researchers recommend mixing one ounce of aluminum sulfate per gallon of water and applying this to each hydrangea. For very large plants, the application may be doubled. Practice restraint and continue to conduct soil tests, as too much aluminum in the soil can be problematic for many plants. Aluminum sulfate applications should not replace efforts to amend soil pH, which will yield much longer-lasting results.

Kim Toscano

Kimberly Toscano is a freelance writer, gardening expert and traveler with an eye on design. Kimberly blends her formal training in horticulture and entomology with her passion for design to educate and inspire gardeners.
View More Articles

Related Articles

Elegant Garden Design Using Gardenias And Hydrangeas

Create lasting impressions with classic Southern plants like Gardenia.

Guide to Hydrangeas: Getting to Know the 4 Main Types

Despite sharing a name, not all hydrangeas are the same.

Demystifying Hydrangea Pruning

How to identify and properly prune your summer bloomers

Plants Featured In The article

Hydrangea
Heaps of white bloom heads on White Wedding Hydrangea

White Wedding® Hydrangea

Hydrangea paniculata ‘LeeP1’ PP28973
Hydrangea
Close-up on White Wedding Hydrangea, cone-shaped blooms in white to cream to lime

Moon Dance® Hydrangea

Hydrangea paniculata ‘LEEP2’ PP29751
Hydrangea
Semmes Beauty Hydrangea's delicate white blooms sit atop oakleaf-shaped foliage

'Semmes Beauty’ Oakleaf Hydrangea

Hyrangea quercifolia ‘Semmes Beauty’
Hydrangea
Large white tightly formed Hydrangea bloom head of Tara Hydrangea from Southern Living Plant Collection

Tara® Hydrangea

Hydrangea quercifolia ‘BIV01’ PP30565
Hydrangea
Heaps of blue to lavender Southern Living Hydrangea bloom heads

Dear Dolores® Hydrangea

Hydrangea macrophylla ‘Wyatt LeFever’
Hydrangea
Close-up on big beautiful round Big Daddy Hydrangea blue bloom head

'Big Daddy' Hydrangea

Hydrangea macrophylla ‘Big Daddy’ PP14527

Join the Conversation!

Where To Buy
Southern Living Plants

{find a garden center near you}

Southern Living Plants Logo
Instagram
Facebook-f
Pinterest
Youtube

Plants

  • Annuals and Perennials
  • Berry Plants & Fruit Trees
  • Groundcovers/Grasses
  • Shrubs
  • Trees
  • Tropicals
  • Vines
Menu
  • Annuals and Perennials
  • Berry Plants & Fruit Trees
  • Groundcovers/Grasses
  • Shrubs
  • Trees
  • Tropicals
  • Vines

About Us

  • About Us
  • History Of The Collection
  • Events
  • Botanical Gardens
  • Testimonials
  • Contact Us
Menu
  • About Us
  • History Of The Collection
  • Events
  • Botanical Gardens
  • Testimonials
  • Contact Us

PRO Resources

  • Brand Resources
  • Marketing Support
  • Fact Sheets
  • Image Gallery
  • Re-Wholesaler Locator
Menu
  • Brand Resources
  • Marketing Support
  • Fact Sheets
  • Image Gallery
  • Re-Wholesaler Locator
©2021 Southern Living Plant Collection