Family: Lamiaceae
Common Name: Sage

Salvia is a huge plant group of over 900 species, comprising shrubs, herbaceous perennials and annuals. Salvias are often associated with red or purple flowers, but there are also species with cream, yellow, white, blue and pink flowers. Many have highly aromatic foliage, with scents ranging from the delicious to the outright unpleasant. The foliage of pineapple sage (S. elegans, 'Scarlet Pineapple'), for example, has a delicious perfume, while bog sage (S. uliginosa) smells rather unpleasant. Culinary sage, S. officinalis, is also one of this group. Most salvias are extremely easy to grow and, once established, need little more than occasional, deep watering in hot weather and some cutting back after flowering. Tall-growing salvias are ideal for the back of borders or as fillers between shrubs. Others of varying heights are suitable for edges or mixed with annuals, bulbs and other perennials. Many salvias have a very long flowering period, through summer into autumn. Some species, like S. leucantha, flower in winter through to spring. Summer to autumn flowering of salvias makes them an asset, as they continue to bloom after many perennials have finished. However, none of them make good cut flowers.

Species

S. azarea, zone 4, a perennial, grows to over 1 m (3 ft) high, with intense, deep blue flowers.

S. elegans 'Scarlet Pineapple', pineapple sage, zone 10, is a tall, attractive plant with long, textured leaves, which smell of pineapple when crushed. The bright red flowers are quite striking.

S. farinacea, mealy cup sage, zone 9, is a short-lived perennial, 30-50 cm (12-20 in) high, often better treated as an annual. It has deep purple or white flowers with a woolly, white coating.

S. guaranitica, zone 9, is very easy to grow, reaching in excess of 1 m (3 ft). It has flowers in the intense blue of S. azurea.

S. involucrata, zone 9, is a vigorous plant, growing to about 1.2 m (4 ft), with bright rosy pink flowers over a very long period.

S. leucantha, Mexican sage, zone 10, is a very useful perennial, the velvety purple and white flowers blooming in winter and spring. The leaves are green with white, felty undersides. This species is also very vigorous, growing 1 m (3 ft) tall, and spreading rapidly by means of under-ground stems.

S. microphylla, zone 9, has bright red flowers.

S. officinalis, common sage, zone 5, is one of the most difficult to grow, demanding perfect drainage and disliking humidity and excessive summer rain. The foliage is gray and rather wrinkled and the flowers are generally pale violet.

S. patens, zone 9, to 60 cm (24 in) high, produces intense, deep blue flowers.

S. uliginosa, bog sage, zone 9, bears bright blue flowers, with a touch of white, from summer into autumn. This long flowering period makes it a useful perennial, despite its rather offensive smell. It can also be rather invasive. It is easy, however, to pull out unwanted plants.

Cultivation

Many species prefer full sun all day, but quite a number will tolerate semi-shade or shade for part of the day. Several can be grown in dappled shade, under trees. Any well-drained soil is suitable, while mulching with decayed manure in early spring will improve the condition of the soil. Water regularly to establish; once established, they can be drought-tolerant, although occasional, deep soakings during dry periods will encourage better growth and blooming. However, poorly drained soils and overwatering may kill these plants.

Apply complete plant food or pelletted poultry manure in spring in poor soil, but too much fertilizer will result in all foliage and few flowers.

Tip prune after each flowering flush to promote further blooming. In late autumn or early winter, cut plants off just above ground level. To avoid lifting and dividing the clumps, wait until new growth begins in spring, then simply thin out crowded growth. Propagate from seed or cuttings. In frost-prone climates, the frost-tender species can be grown in a cool greenhouse or conservatory, or planted out for the summer. Grow in pots of well drained, soil-based potting compost and ensure maximum light, but shade from direct sun. Keep humidity low.

Climate

There are salvias suited to various climatic zones, but many are frost-tender.