Swanleaf Clouding Sage

Salvia yangii is a deciduous perennial subshrub with an erect to spreading habit. Superficially, it resembles a much larger version of lavender. Multiple branches arise from a shared rootstalk, growing to a height of 0.5–1.2 metres (1+1⁄2–4 feet), with occasional specimens reaching 1.5 m (5 ft). The mature plant may be 0.6–1.2 m (2–4 ft) across. The rigid stems are square in cross-section, and are covered by an indumentum formed by stellate, or star-shaped, trichomes and oil droplets. Especially during autumn, these hairs give the stems a silvery appearance. The grayish-green leaves are arranged in opposite pairs, and attached to the stems by a short petiole. They are generally 3–5 centimetres (1+1⁄4–2 inches) long and 0.8–2 cm (1⁄4–3⁄4 in) wide, although narrower in some populations. The overall leaf shape is oblate, a rounded shape longer than it is wide, to lanceolate, shaped like the head of a lance. They are pinnatipartite, with a deeply incised leaf margin that may be either wavy or sharp-toothed; even within a single community of S. yangii, there can be considerable variation in the details of leaf shape. Leaves near the top of branches may merge into bracts. The foliage is aromatic, especially when crushed, with a fragrance described as sage-like, a blend of sage and lavender, or like turpentine. The flowering season of S. …

Widely distributed across Asia in its native range, S. yangii grows in western China, northwestern India, Pakistan, Afghanistan, Iran, Turkey, and parts of eastern Europe. It is found in steppes and on hillsides, and grows at higher elevations in mountainous regions, including the Himalayas. It has been recorded at 10,000 ft (3,000 m) of altitude in the Karakoram. In Pakistan's Quetta district, it is often found in association with the grass Chrysopogon aucheri, and may serve as an indicator species for soils with low calcium carbonate and chloride availability. The harsh habitats preferred by S. yangii are comparable to the sagebrush steppe of North America.

In parts of its range, such as the Harboi, these steppe ecosystems are employed as rangeland for grazing animals such as sheep and goats, although this forage is generally of poor nutritional quality. S. yangii can serve as an important source of phosphorus and zinc, despite being high in poorly-digested material such as neutral detergent fiber and lignin.

Russian sage has a long history of use in traditional medicine, and is smoked as a euphoriant. In addition to its use in folk medicine, it is sometimes used in Russia to flavor a vodka-based cocktail. Its flowers are eaten in parts of Afghanistan and Pakistan, including Kashmir, adding a sweet flavor to salads. This species is considered a candidate for use in phytoremediation because of its rapid growth, tolerance for harsh conditions, and ability to accumulate toxic heavy metals from polluted soil. The essential oil can function as a biopesticide, especially regarding Tropidion castaneum beetles and Camponotus maculatus carpenter ants.

Following its introduction to the United Kingdom in 1904, the Irish gardener and author William Robinson was immediately taken with the plant, which he described as being "worth a place in the choicest garden for its graceful habit and long season of beauty." The Royal Horticultural Society records the establishment of cultivars beginning with P. 'Hybrida', selected at a Hampshire nursery in the 1930s. By the late 1980s and early 1990s, S. yangii had gained widespread popularity, and in 1995, it was selected as the Perennial Plant Association's Plant of the Year. The cultivar 'Blue Spire' has gained the Royal Horticultural Society's Award of Garden Merit.

Planting and care. Russian sage is a perennial plant suitable for a wide range of conditions, at least where its tendency to spread will not be a problem. The species prefers full sun. Specimens planted in partially shaded locations tend to spread or flop, although this behavior can be controlled somewhat by pinching young shoots or by providing a strong-standing accompaniment that the plant can drape itself around for support. Flowers bloom only on new growth. …