Plectranthus fruticosus aka Forest Spur Flower

Plectranthus fruticosus, or forest spurflower, is a shrub. It stays green all year. It belongs to the mint family, Lamiaceae. Its home range runs from southern Mozambique into South Africa. It grows in forests, scrub forest, and shaded rocky sites. Gardeners grow it for its looks. People also gather wild plants for use as medicine.

The shrub grows many branches and forms a bushy shape. Most stems grow upward, though some may trail along the ground. Garden plants reach about 5–8 feet [1.5–2.5 metres] tall and wide. The flora account gives a shorter range of 2–6.6 feet [0.6–2 metres]. The RHS gives two to five years to reach full size. Green leaves have toothed edges and veins that show well. Touch or crush the leaves or branches, and they give off a strong scent. Some people do not like the smell.

Small purple flowers grow on upright spikes from June to August. Each flower forms a tube with two lips. Insects carry pollen between the flowers. The spikes rise above the green leaves and add summer colour. Remove faded flower clusters, called racemes, to help the plant grow more flowers. Its leaves add interest when the plant is not in bloom. They stay green all year.

The sources differ on the best light for this plant. The RHS favours full sun but also accepts part shade. Useful Tropical Plants says it prefers shade. Choose a site with shelter and sandy or loamy soil. Keep the soil moist, but let water drain well. Acid, neutral, and alkaline soils all suit it. The RHS rates it H2: it withstands cool weather but not freezing. Move plants outdoors only once the risk of frost has passed. Large pots suit summer patios. Give them frost-free cover for winter. The plant also suits greenhouses and conservatories. Prune plants that have settled in by up to one-third in late winter. This helps keep growth compact before spring shoots appear. Grow new plants from seed, softwood cuttings, or semi-hardwood cuttings.

The RHS reports few pest or disease problems. Useful Tropical Plants lists no known food uses. It reports use for burns and action against microbes. People also use the plant to keep insects, including flies, away. These uses do not show that it is safe to eat. Research cited there reports harm to embryos and fetuses in rodents. That evidence does not place it in a specific toxicity class for humans or pets.