There are more than 900 species of salvia, including shrubs, herbs, perennials and annuals. Like other members of the mint family, the salvia's leaves are directly opposite each other on a four-sided stem. All salvias produce flowers (most commonly blue, red or white) in clusters along a spiky stem. Each individual flower is tubular in shape and divided into two parts. Salvia may also be referred to as sage, although usually those plants used for cooking are called sage, while those grown as ornamentals are called salvia.
The name salvia comes from the Latin word meaning "to heal", since the plant was believed to have medicinal properties. In ancient Greece it was used to treat a variety of conditions including consumption and snake bites. The ancient Romans performed a special ceremony for harvesting salvia, which they considered a sacred herb.
Salvia splendens, or scarlet sage, is an annual often used as a bedding plant. The red-flowered variety is most common, though it can also be found in white, purple or blue. Plants can be anywhere from 6 to 24 inches high, with the taller varieties blooming later than the short varieties.
Salvia farinacea, or mealycup sage, is a tender perennial hardy to zone 6 (it may overwinter in colder areas with some protection). Two cultivars are Victoria Blue and Victoria White, both 18 to 24 inches tall. Mealycup sage makes a good cut flower and also dries well, retaining its blue color.
Salvia elegans, or pineapple sage, is grown as much for its pineapple scented leaves as for its edible bright red flowers. Leaves and flowers can be used in salads, teas or as a garnish.
Perennial and Biennials
A number of attractive salvia hybrids are available for garden borders. May Night, voted the 1997 Plant of the Year by the Perennial Plant Association, has foot-high deep indigo flower spikes. It reaches 18 to 24 inches tall. Another favorite is the violet-flowered East Friesland, whose leaves are more finely textured than those of May Night.
Salvia sclarea or clary sage is a biennial with large woolly leaves and pink, cream or blue flowers. It has a distinctive scent.
Salvia argentea, or silver sage, is a biennial or short-lived perennial grown mainly for its large leaves which are covered with downy silver hairs. In early summer it produces white flowers on 2-foot-high stems. It requires a dry soil to prosper.
Common sage, Salvia officinalis, is technically an herb, but it can also be used in the flower border for its grey-green leaves. Hardy to zone 5, it is woody-stemmed but frost tender. Variegated varieties are also available.
Salvia prefer a location in full sun, and like a loose well-drained soil with added organic matter. Fertilize monthly. Although salvias have few pests or disease problems, cool wet weather may encourage fungal diseases. Most salvias benefit from deadheading to neaten the plant and encourage branching. Perennial salvias can be divided in the spring.
The blue and purple flowered varieties are particularly nice when used as a foil for yellow and gold plants, such as coreopsis Moonbeam, Stella d'Oro daylilies or achillea Coronation Gold. They are also striking when paired with silver-leaved plants like lamb's ear and dusty miller. All salvias are attractive to butterflies and hummingbirds.