Salix Shrubs and Willow Trees
Common name: Willow
This large genus includes many that are large trees. But there are also plenty of good garden shrubs, with some low-growing and ground hugging examples. Willows are grown principally for their impressive displays of catkins in the late winter and spring.
Popular species and varieties
One form that has a low-growing habit is Salix lanata (AGM), which does not grow more than 1m (36in) in height, but can easily exceed this figure in spread. It has soft, silvery foliage and woolly, yellow-grey catkins that can be up to 10cm (4in) long. The variety ‘Stuarti’ can have even longer catkins. Salix hastata ‘Wehrhahnii’ (AGM) also grows to around the same height. It was discovered in Switzerland in the early 1930s and has wonderful silvery grey catkins. Another, also from the Alps, is S. helvetica (AGM), a neat bushy shrub that grows to around 60cm (24in) and has a profusion of silver-grey catkins.
One very desirable salix which was discovered in the 1870s growing on a Scottish mountainside, is S. x boydii (AGM), undoubtedly the slowest growing — even after many years it may still be just 75cm (30in) in height It forms a small gnarled shrub with downy grey-green leaves. Only very occasionally will it produce catkins. It is a good subject for the rock garden.
In the late 1970s, S. integra ‘Hakuru Nishiki’ was introduced; it is very different to those already mentioned. Raised in Japan, it has white blotched foliage held on polished stems. It is very effective in a waterside planting, but can burn in very strong sunlight — a lightly shaded spot is best.
Soil type Most moisture-retentive soils are suitable.
Planting Willows are happy in sun or light shade. Planting can be done whenever conditions are suitable, between early autumn and late winter.
Pruning Generalis not required, but any damaged or unwanted branches can be removed in late winter.
Propagation Hardwood cuttings around 22cm (9in) long may be taken from early autumn; root them in a nursery bed.
Pests and diseases Caterpillars, aphids and scale insects can be a problem: treat with suitable insecticide as soon as seen.