How To Change the Colour of Hydrangea Flowers

Does your garden need a bit of a change in colour? Look no further! We can teach you how to change the colour of one of your favourite flowers Hydrangeas.

Hydrangea plants are versatile, meaning that they can be altered in colour to suit your garden needs. Scientists have found that by altering the pH scale in the soil depending on the acidity or alkalinity, you can change the colour of certain plants.

The pH scale ranges from 1 to 14 and is centered around neutral (7). If the soil is less than 7, it will be acidic – if it is higher than 7, it will be alkaline.

Turning Hydrangea Flowers Blue

There are two important elements that are needed:

  • The soil needs to acidic (approximately at pH 5.2-5.5)
  • The soil needs to have aluminium present

The plant will only absorb the elements if the pH is correct in the soil. Therefore for the Hydrangeas to turn blue, the plant will need to absorb the aluminium. The plant can only do this if acid is present in the soil.

What do I need to add to the soil to change the pH level?

  • Organic material such as compost, manures and mulch
  • Iron sulphate
  • Aluminium sulphate
  • Sulphur

Turning Hydrangea Flowers Pink

There is one thing that is needed:

  • Block the absorption of aluminium by the plant

By increasing the pH of the soil to neutral, the Hydrangea will usually turn pink.

What do I need to add to the soil to change the pH level?

  • Agricultural lime – a few times a year