pH value of blue hydrangeas

Dear hydrangea friends,

The color of your hydrangea blossoms depends not only on the variety, but also significantly on the pH of the soil . If you want to enjoy the delicate blue or purple blooms , a slightly acidic soil is crucial – with a pH between 4.5 and 5.5 .

Many pink-flowering hydrangeas can be converted to blue with suitable soil and proper care. Some red-flowering varieties also develop a beautiful purple color with targeted application of aluminum sulfate and a low pH.

To achieve this, regular pH monitoring is particularly important – both in the bed and in the flowerpot , in the planting hole , and when mixing special soils . Only when the pH is correct can the aluminum in the soil be absorbed by the plant – a prerequisite for the desired blue color.

How can you easily check the pH value?

There are practical and cost-effective solutions available today:

• pH test strips – ideal for quick tests in irrigation water or soil solution

• Digital pH meters – precise and reusable, also for regular checks in beds or pots

Through regular monitoring and targeted soil adjustment, impressive blue coloring can be achieved – entirely by chance. It's best to combine pH control with a suitable hydrangea fertilizer and, if necessary, with aluminum sulfate .

Sincerely
Your team from Hydrangea World Ullmann 🌿