Salvia splendens aka Bonfire Salvia

Salvia splendens, or scarlet sage, belongs to the mint family. It comes from Rio de Janeiro in Brazil. Kew places it in a tropical climate with seasonal drought. It is a tender perennial with a partly woody base. Gardeners often grow it as an annual where winters are cold. Its upright, bushy form suits beds and pots.

Garden size varies between the sources. NC State gives heights of 1–3 feet [0.3–0.9 metres]. RHS describes smaller plants reaching 1.6 feet [0.5 metres]. Reported widths range from 0.7–1.6 feet [0.2–0.5 metres]. The plant grows fast and has green, square stems. Its green leaves grow in pairs on short stalks. Each simple leaf has an oval shape and a pointed tip. Rounded teeth line the edges, and the surfaces lack obvious hairs.

Flower spikes rise from the ends of the stems. Small flower groups form whorls along each spike. The blooms are red to scarlet and have long tubes. Each flower has two lips, with longer upper lobes. Red calyces add colour around the short-lived blooms. Flowering lasts through summer and autumn, often until frost. The calyces remain around the fruit but lose their colour. Each small, black fruit splits into four nutlets. Each nutlet holds one seed. The flowers draw hummingbirds and butterflies.

Give scarlet sage warm conditions and soil that drains well. RHS recommends full sun, while NC State also allows part shade. Fertile soil with plenty of organic matter supports growth. Keep the soil moist and water during dry spells. This plant does not tolerate drought. RHS rates it H1C, for outdoor growth in warm summer conditions. Pinch young shoots to help the plant branch. Remove spent flower spikes after bloom. Raise new plants from seed or stem cuttings. Seeds need light, so leave them uncovered when sowing.

Use scarlet sage in borders, cottage gardens, or bedding displays. Smaller plants suit edging and containers. The flowers also work as cut stems indoors. Garden plants tend to have few pest problems. Slugs may attack them, and greenhouse pests include aphids and whiteflies. Spider mites, seedling damping-off, and botrytis can also cause trouble. Other risks include powdery mildew, wilt, and root or foot rots. Honey fungus is a rare problem. The supplied evidence does not establish edible uses or toxicity.