Hydrangeas are a guaranteed way of adding colour to your garden, with the showy flower coming into bloom from mid-summer to early autumn. Available in shades of pink, white or blue, they can make for an eye-catching display, but it’s not always guaranteed that their petals will produce vibrant blooms.

If you’ve previously noticed your hydrangeas have been slightly pale-looking, this could be due to a number of factors, especially if they’re not planted in the right location. Excessive sun can lead to hydrangeas becoming dehydrated and wilting, and it’s best to place them in a semi-shady spot where they won’t be exposed to harsh afternoon sunlight. Getting the soil right is also crucial to hydrangea displays, and adding coffee grounds to soil is an easy and affordable way to ensure striking blue blooms. 

Although getting enough sunlight and water is crucial to taking care of hydrangeas, the colour of the flower is mostly determined by the pH level of the soil. Blue displays require more acidic soil to bloom, which coffee grounds can help maintain. 

While there are plenty of different varieties of hydrangeas, they all enjoy similar growing conditions. However, achieving a dazzling display of pink flowers requires slightly different soil care than that required with blue blooms.

According to the Royal Horticultural Society (RHS), pink hydrangeas require more alkaline soil than acidic soil, which has a pH level higher than 7.0.

A soil’s pH level depends on the matter it’s made from, and if you’re not sure what pH your soil is, you can simply use a DIY kit that’s sold at most garden centres and B&Q to test this.

There are a number of products you can add to soil to raise the pH levels and make it more alkaline, including baking soda and even crushed eggshells, but one material is particularly effective for pink displays. 

Commonly referred to as garden lime, ground limestone can dramatically improve the appearance of pink hydrangeas by making the soil more alkaline. 

While hydrangeas are best planted in well-draining soil that isn’t too moist or wet, lime should be added early in the spring or autumn before the growing season, as it can take some time for pH levels to change. 

It’s best to add lime on a dry and windless day when soil is damp, mulching it into the top 20 cm or so layer by digging over the ground afterwards, but make sure to wear protective clothing while doing this as it can irritate skin. 

Mixing shades of hydrangeas can make for a stunning display, and this method for achieving dazzling pink hydrangeas can work well alongside white, red and green varieties as they won’t change shade regardless of the soil’s pH level.