Big, Bold and Beautiful

The soft clouds of hydrangea flowers are a promise of summer. Let’s take a closer look at growing these plants.

Hydrangeas are old favourites, beloved for their big blowsy blooms. They look great with their traditional garden partners, such as camellias and azaleas, but are also a stunning feature on their own.

How to grow

All hydrangeas bloom and grow well in morning to midday sun if they have enough water. They thrive in dappled sunshine and afternoon shade. No hydrangea will do well in heavy shade, such as that found under big trees or in the shadow of your house.



Hydrangeas grow well in pots, especially the small varieties. Use a premium potting mix and keep them well watered through summer. Set your pot on a stand or pot feet to encourage drainage and prevent water-logging. Repot every two–to–three years. Plant them in plastic pots that can fit inside decorative pots and be easily removed after flowering.



These are thirsty plants, so grow them in pots if you can’t keep the whole garden well-watered in summer. 

Changing colour

Hydrangeas are unique in that the flower can change colour, depending on the pH of the soil. To turn a blue hydrangea pink, apply dolomite lime several times a year. Aim for a pH 6.0–6.2. Levels higher than this will cause iron deficiency. Use a fertiliser high in phosphorus, such as Phostrogen, to help prevent aluminium uptake.



To turn a hydrangea blue, it needs aluminium. A solution of 1 tbsp of aluminium sulphate forevery 3.5 litres of water will lower the pH (aim for 5.2–5.5). Water the solution into the soil around hydrangeas each month throughout the growing season. Alternatively, use Yates Hydrangea Blueing Tonic. White flowers don’t have any pigment so won’t change colour.

Hydrangea types

Hydrangea macrophylla

The blue or pink flower heads change colour depending on the pH of the soil. They prefer an easterly aspect for good morning sun and grow 1-3m. Prune lightly in autumn or winter. Plant with hellebores to distract from bare stems.

Hydrangea petiolaris

The climbing hydrangea is one for cold climates and you may have seen it smothering the cool side of an English stone cottage. It’s deciduous and likes the cool shade of the south side of the house and regular water. Flowers, pure white and lacecap in form, pick often.

Hydrangea quercifolia

This is a standout shrub under trees, 1m x 1m, loved for its long flower panicles and scalloped oak-like leaves which colour brilliantly in autumn. The flowers age into dusky pink, caramel and chocolate-russet tones and as a bonus these hydrangeas tolerate more sun than others and don’t require as much water. Look for ‘Snow Queen’ or the double ‘Snowflake’.

Hydrangea paniculata ‘Grandiflora’

Large panicles of flowers can reach a sensational 30cm long and cover the entire shrub, fading to pink as they age. This large, cold-tolerant shrub prefers full sun and is often used as a hedging screen. Prune lightly as soon as flowering is finished for even more flowers next summer. Look out for the pink form ‘Sundae Fraise’.

Hydrangea arborescens ‘Annabelle’

This hydrangea has the most beautiful large, flower head! Lime-green buds open to pure white. Flowering all summer long, and eventually ageing to a beautiful green before finally drying on the bush in late autumn. She is a fast-growing variety best suited to a moist part shade position in the garden.

Hydrangea macrophylla: Endless Summer Collection

If your only complaint about hydrangeas is their once-a-year flowering, you’ll love this non-stop variety. The ‘Endless Summer’ collection features a range of hydrangeas, including mophead and lace-cap types that repeat flower from early summer to autumn (with regular deadheading). Colours range from classic blue through to pink and soft white. In the landscape, individual flower tones vary with soil pH, from blues to pinks.



Where to buy: Visit nurseries in our Garden Clinic Nursery Network throughout early summer to find the best specimens.