Hydrangea macrophylla Constellation

Hydrangea macrophylla 'Constellation' is an old variety, yet still popular for its particularly abundant flowering. From July to September, it is covered with large, dark pink to red ball-shaped inflorescences. It forms a compact bush of medium size, which can also be grown in a container. Hardy, plant it in a semi-shaded to shaded situation, in non-limestone soil. It is easy to grow, requiring only annual pruning in spring and watering in summer to keep the soil moist. 

Hydrangea macrophylla is a deciduous bush, native to Japan, where its beauty has been appreciated for centuries, and mentioned in poems dating back to the 8th century! Festivals are even dedicated to this bush. It can be found in the wild on the island of Honshu (which is home to the capital Tokyo), and it was introduced to Europe around 1789. It belongs to the Hydrangeaceae family, which also includes the widespread deutzias and philadelphus, and a dozen other less known genus.

'Constellation' has an uncertain origin, but may be an English variety from 1929. It is a variety that has stood the test of time, and is still much appreciated for its abundant flowering. This fairly compact bush, reaching approximately 1.3m (4ft) in height and 1m (3ft) in width at maturity, has a particularly dense habit. It bears beautiful dark green leaves, with a slightly dentate border, with well-marked veins giving them a waffled appearance and a shiny surface. This mass of foliage forms the perfect setting for the flowering composed of many round heads, 10 to 15cm (4 to 6in) in diameter. Composed of 4 petals with a delicately crafted border, these flowers are a dark pink shifting towards red.

It is not strictly an ericaceous plant. It prefers neutral to acidic, rich and slightly moist soils. Easy to grow, it can live for a very long time and can be planted in a container to decorate a shaded corner of a terrace. Planted in the garden, this small bush will brighten up a shady area with its bright flowering. Plant it with other flowering plants with similar needs, such as Clethra alnifolia 'Hummingbird', whose fragrant white spikes will contrast well in shape and colours with the flowers of 'Constellation', and whose colourful autumn foliage will end the season beautifully. For spring, choose Fothergilla gardenii, a small bush unjustly overlooked, whose white bottlebrush flowers scent the garden in April-May, while its leaves blaze with yellow, orange and purple in autumn. To extend the flowering season as long as possible, go for Stachyurus praecox, another rarity that is nonetheless easy to grow, with cute floral clusters of pale-yellow bells and beautiful autumnal colours.