bloom in a variety of colours, so there's guaranteed to be one that suits your aesthetic. You can choose from a variety of whites, greens, purples, pinks, blues and even variegated options. Blue hydrangeas are the envy of gardeners everywhere. Even though other have blue blossoms, nothing quite beats the large spherical blue of a hydrangea.

Those with stunning pink hydrangeas often want to turn them blue, and there could be a natural way to do so. But when you hear of the magical, colour-changing abilities of these enchanting plants, this relates to a specific variety called Hydrangea macrophylla, or "Bigleaf Hydrangea".

Bigleaf hydrangeas are known to bloom in shades of pink, blue, or white. While white varieties will remain pure and untouched by colour regardless of what you do, pink and blue hues can be influenced by the soil they grow in.

The secret to changing the colour of hydrangea flowers isn't what's applied to the blooms themselves, it has to do with the chemistry of the soil.

Taking to the Creative Gardening page on Facebook, Janet Scott raved about the powerful abilities coffee grounds had on turning her hydrangeas blue.

She said, "My hydrangeas have turned gorgeously blue and have been growing like crazy since using coffee grounds."

Other group members shared their thoughts on this. Lori Jagon wrote: "I do the same at the beginning of spring through till autumn and have beautiful blue blooms."

Kat Niman commented: "Coffee will act as a fertiliser and help produce blue blooms due to the acidity. You can go ahead and add it now.

"Depending on the bloom colour you'd like, you can adjust the pH by using other additives."

So, how does this work? Well, the more alkaline the soil is, the pinker the blooms will be. At neutral pH, some varieties remain pink while others will start showing hints of blue with lovely shades of lavender.

Blue hydrangeas tend to bloom better in acidic soils, usually with a pH of 5.5 or less.

Simply work the coffee grounds into the soil before watering. The colour change will happen gradually, so it might take an entire year of doing this consistently for it to reach the right acidity.