Hydrangea macrophylla Blauer Zwerg

Hydrangea macrophylla 'Blauer Zwerg' is a floriferous variety with a compact habit, which has proven itself in the garden as well as in flower pots. This bush, about 1.2m (4ft) tall and 1m (3ft) wide, forms medium-sized ball-shaped inflorescences with a beautiful intense blue colour in acidic soil, or a purplish blue in more neutral soil. They continue to bloom throughout the summer against a backdrop of glossy, deep green foliage. This variety is hardy, easy to grow, and has sturdy stems that give it good stability in the garden.

Hydrangea macrophylla 'Blauer Zwerg' was obtained in Germany in 1965 by August Steiniger. It is one of the many hybrids resulting from the cross-breeding of hardy species. They belong to the Hydrangeaceae family, native to China and Japan. This shrub has a bushy and compact habit, reaching a height of about 1.2m (4ft) tall and 1m (3ft) wide at maturity. From July to September, its sterile flowers form round inflorescences. Their colour ranges from purplish pink to dark and intense blue depending on the acidity of the soil. They are carried by sturdy stems, one year old or older. The flowering is accompanied by small, resistant, bright green foliage that takes on carmine purple hues in autumn before falling. The leaves are opposite, reaching about 10cm (4in) in length. They are simple, ovate to elliptical, ending in a pointed tip, and strongly toothed like a saw. Hydrangeas can live for at least 50 years.

'Blauer Zwerg' is a superb variety, with excellent hardiness and very generous flowering. Hydrangeas are well known for brightening up the north side of houses. This one will thrive in an east or west exposure that is not too hot, both in flower beds and hedges. This variety is suitable for cultivation in the ground or in containers, which can be placed on a terrace or near an entrance. Although these plants dislike limestone, they are not strictly speaking ericaceous plants. Pair them with bush fuchsias or annual impatiens, or plant spring-flowering bulbs in front of their round silhouette. Enjoy their sumptuous flowering in the garden or in the house for a long time.

Note: The colour of the flowers of macrophylla hydrangeas varies depending on the soil pH. Traditionally blue varieties turn pink in neutral or alkaline soil. To maintain a beautiful blue colour, mix ericaceous soil with your garden soil and apply aluminium sulphate (slate contains it) or alum stone every spring.