Salix rosmarinifolia - Narrow-leaved Rosemary Willow

Salix rosmarinifolia, the rosemary-leaved willow or rosemary willow, is one of the most beautiful bushes with grey foliage. Despite a well bushy and very dense habit, there is a great sense of lightness that emanates from this shrub. The wind plays delicately in its foliage, creating silvery highlights on the underside of its silky leaves, which are a bluish-grey colour on the top side and white on the underside. Its spring flowering appears in the form of small grey woolly catkins that turn yellow when ripe, before the leaves emerge. In winter, its fine branches are revealed, which gradually turn red. Tolerating a wide range of soils, fast-growing and perfectly hardy, this shrub is perfect for creating a low hedge, either trimmed or left to grow freely and naturally.

Salix rosmarinifolia, also known as Salix elaeagnos subsp. angustifolia, S. repens var. rosmarinifolia, S. anomala, S. minutiflora var. pubescens, S. sibirica or S. pubescens, belongs to the Salicaceae family. It is a deciduous botanical species native to central and southern Europe and Turkey. It is a pioneer species found in wet areas, preferring heavy clay-loam soils. The plant is quite polymorphic in nature, adapting its growth and habit to its living conditions. Rosemary willow is a slightly suckering shrub, which tends to spread laterally over time. It has a characteristic, globular, dense and bushy habit, supported by thin flexible branches. At maturity, this fast-growing willow will reach an average height and width of about 1.5 m (4.9 ft), sometimes up to 2.5 m (8.2 ft). The young branches are pubescent and reddish-brown in colour. They develop a beautiful red colouration, providing wonderful winter colour when the shrub is leafless. The deciduous foliage consists of linear, lanceolate leaves, measuring 5 cm to 10 cm (2 in to 4 in) in length, covered in shiny bristles. The leaves are bluish-grey-green on the upper side and very silvery-white on the underside. Flowering occurs from March to May, before the leaves appear, on separate male and female plants. The male catkins are grey when they first emerge, then turn yellow to reddish as the stamens mature. The female catkins are more discreet. The fruit is a capsule that opens to release seeds with long bristles. This flowering provides a source of pollen and nectar for bees.

This small willow, which forms a light, moving and silvery mass, finds its place on the edge of water features, but also on drier slopes as long as the soil is deep and retains some moisture. It can also be used in rock gardens or to create low, natural hedges that require minimal maintenance in a slightly wild area of the garden. Regular pruning after flowering is recommended to encourage the shrub to become bushier and produce numerous flowering branches. For example, it can be planted alongside dogwoods (Cornus sanguinea, C. sericea), miscanthus, gorse or reed mace at the edge of a large pond. In a hedge, its silver foliage will complement the purples of Berberis, Physocarpus 'Summer Wine' or Cotinus 'Royal Purple'.

There is such a diversity of forms, sizes and cultivation requirements among willows that it is impossible not to find a subject that will thrive in your garden. These shrubs and trees are generally easy to grow if their basic requirements are met. In the garden, a willow always brings a bucolic and natural touch, sometimes unique or romantic depending on the variety.