Hydrangeas are the flower of summer. Stunning when seen on mass display, they have a fascinating flower. It looks from afar like a big powder puff, but on closer inspection has multiple little flowers within it. It is also unlike most flowers, in that they can change colour.

Blue hydrangeas – photo Jenny Esots
Pink or Blue?Hydrangeas can bloom in pink and blue and a huge range of shades in between pink and blue. It is much easier to change a hydrangea from pink to blue, than it is from blue to pink. However white hydrangeas cannot be changed to blue or pink. Hydrangeas change colour (except for the white ones) based on the pH level of your soil. The more alkaline the soil, the pinker the flowers. To make pink hydrangeas turn blue (or to keep your blue ones from turning pink), increase the acidity of your soil. A soil acidifier can be bought from your local nursery and applied to intensify the blue tones.

Blue hydrangeas – photo Jenny Esots
Coffee grounds are useful
Or you can add organic materials to your soil to make it more acidic. Coffee grounds can be used. So can ground-up citrus peel. Work the mixture into the soil around the base of your hydrangea plant, and then water it in.

Blue hydrangeas – photo Jenny Esots
Save your peels and your coffee grounds in a little bowl in the kitchen and whenever the bowl is full, take it outdoors to feed the hydrangeas. The acidity of the of the soil will slowly increase; by next year, your hydrangeas should be looking a lot more blue.

Pinky purple hydrangea – photo Jenny Esots
Crushed egg shells will also increase the acidity of the soil. Work them into the soil along with citrus peel and coffee grounds. It is possible you'd prefer pink hydrangeas. If so, you can make your soil more alkaline by adding garden lime, again buy this at your local nursery.

Hydrangeas, the Flower of summer – photo Jenny Esots
All kinds of ColourHydrangeas come in all kinds of colours as they graduate in between pink and blue. They can be so subtle in shade to vivid splashes of colour. Purple shades are also possible. When seen on mass they are stunning. Sydney-siders love their blue hydrangeas, but with the right soil conditions any colour is possible in any place.

Hydrangeas in all kinds of colours – photo Jenny Esots
Growing HydrangeasMany people think hydrangeas are a high maintenance plant. But they are remarkably hardy and survive well in pots. They do require watering on a hot day, you will see there leaves droop, so give them a drink.

Pink hydrangeas – photo Jenny Esots
Hydrangeas of all colours put on quite a display over summer and autumn and are well worth a try for novice gardeners. Whether you are a blue or a pink person (maybe both) these flowers are glorious.

Blue hydrangeas – photo Jenny Esots