ORNAMENTAL WILLOWS (SALIX SPP.) FOR ALPINE AND SMALL URBAN GARDENS

Journal of Arboriculture, Mar 2004 by Kuzovkina, Yulia A, Quigley, Martin F

ORNAMENTAL FEATURES AND USES OF LOW-GROWING WILLOWS

Low-growing Salix species are versatile enough for numerous ornamental applications. They are not "utilitarian shrubs" as are their lowland relatives (for instance, the large species used for embankment or riparian stabilization) but rather a specialty plant material.

The principal and most recognizable features of willows are their inflorescences, or catkins. Willows are dioecious and, in general, male plants have showier and more attractive inflorescences than females. However, some species also have attractive female inflorescences (S. pyrenaica, S. vanegata).

Many small willows exhibit ornamental qualities year round. The texture of foliage canopies ranges from very fine (S. purpured) to coarse (S. bicolor, S. reinii). Many species can be grown for their foliage (rather than for spring flowering) and with their early leaf break, they provide the first green color in the spring landscape. In summer, dark green, blue, yellow-green, gray, or intense silvery foliage provides effective contrasts to other plants. Many species retain clean leaves throughout the season, though a few begin to yellow or spot by summer's end.

Even leafless shrubs with bare stems and varying forms of ascending or pendulous habit can add interesting architecture to the garden and contribute substantially to the character and appearance of the rock garden. The potential role of willows in the rock garden has been underestimated: Typically, garden books about alpines list no more than two or three willow species. Prostrate species are ideal for cascading over a wall or to cover edges. Small, upright shrubs can make excellent specimen plants, acting as a centerpiece around which the herbaceous composition can be developed. "Alpine-looking" foliage is a major asset of some species such as S. � balfourii, S. helvetica and S. lanata. Interesting crown architecture when specimens are only a few years old can impart an ancient or gnarled look, adding a sense of maturity to the young garden.

Low-growing willow species that grow too quickly for rock gardens can be used as accent plants for the perennial border. Many willows effectively combine with other plants as informal hedges, edging material or grouped for a mass effect. They can also be placed individually as specimens in lawns.

Cultivation of the smallest dwarf species requires special attention because overshadowing by larger specimens and weeds could destroy the specimen. Many of them can be planted into troughs and other permanent containers to ensure their survival and improve display. Some truly dwarf species such as S. herbacea, S. lindleana, and S. reticulata can be used as miniature plants in model railways gardens. Medium-sized willow species make complementary companions to Calluna and Erica in heather gardens along with other low-growing shrubs such as Pinus mugo and Betula nana. Slow-growing alpine species (S. repens, S. helvetica) are commonly trained as bonsai. Species also having attractive catkins are effective specimens for early spring exhibition.