At this time of year you do not have to look far to see walls and pergolas festooned with racemes of beautiful, fragment flowers thanks to wonderful wisteria.
These deciduous, twining climbers flower in the spring, with occasional summer flowers, spectacularly showing off their beautifully scented flowers in shades of white, blue, purple and pink.
Of the ten species available the most commonly grown are Wisteria floribunda (Japanese wisteria), W. sinensis (Chinese wisteria) and their cultivars. Wisteria sinensis produces its flowers before the leaves appear, which can look spectacular in spring and has stems that twine anticlockwise. Wisteria sinensis is the species most suitable for walls where its shorter racemes are displayed to advantage. Wisteria floribunda bears leaves and flowers at the same time and has stems that twine clockwise. The long racemes are shown to best effect on garden structures such as pergolas where they can hang free, unimpeded by branches or foliage.
Wisterias flower best when grown in full sun, but will tolerate slight shade. They require well-drained, fertile soil and should not be allowed to dry out, particularly when becoming established. All species are strong-growing and capable of reaching a height of around 10m (30ft) or a spread of up to 20m (60ft) and as such are ideal for training into trees and covering garden structures.
When choosing wisterias always select one grown from cuttings or by grafting. Seed-raised wisterias take longer to flower and flower less reliably. Grafted plants can be detected by the visible graft union near the base of the stem. Named cultivars are almost always grafted, whereas species plants may not be and most will begin flowering within 3-4 years of planting.
Although usually thought of as climbers, wisterias may easily be grown in containers and even trained as a standard. This is particularly suitable for smaller gardens. When doing so use a quality loam-based potting compost and feed regularly.
Wisterias have a reputation of being complicated to prune, which isn’t the case at all. Regular pruning consists of shortening new growth firstly in August and again in February. There are many straightforward guides available and once mastered, will result in a much-improved flowering display. With patience and a little effort your wisteria will reward you with one of the most glorious sights spring has to offer.