Hydrangeas are some of the most sought-after flowering shrubs due to their incredible blooms and versatile nature. One of their unique aspects is their ability to change colour, especially shifting from pink to mesmerising shades of blue. Many hydrangea varieties have pink, blue, or purple blooms, but macrophylla or serrata hydrangeas are the only ones that can be changed in colour.
What colour blooms your hydrangeas will deliver depends on the pH level of the soil in which it’s planted.
The higher the acidity (pH less than six), the more blue your blooms, while more alkaline soil (pH greater than seven) typically results in pinkish flowers.
To guarantee blue blooms from your hydrangeas, you’ll have to ensure your soil falls into the acid category. Apple cider vinegar can help increase the acidity levels, claimed Mel.
For this method, she instructed: “Mix one cup of apple cider vinegar with 10 litres of water (an average watering can’s worth) and direct the solution at the base of the hydrangea, avoiding the leaves.
“Do this every couple of weeks and the colour will gradually change. You can control the ‘blueing’ by reducing or discarding the vinegar when they develop the desired hue.”
Gardening experts at Gardenia also recommend this household hack for turning hydrangea blooms blue. They said, “Vinegar, particularly white vinegar or apple cider vinegar, can lower the pH when applied to the soil, making it more acidic. This can encourage blue blooms in hydrangeas.”
However, they urged gardeners to take caution with this. They said: “It’s important to use it sparingly, as excessive acidity can harm the plants.”
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