Coleus forskohlii (Brazilian Boldo / Abyssinian Coleus / Blue Spur Flower), photograph by Dinesh Valke; CC.
Coleus scutellarioides (Coleus / Painted Nettle), picture by Teresa Grau Ros; CC.
Coleus Growing and Care Guide
Common Names: Coleus, Painted Nettle, Flame Nettle. Life Cycle: Half hardy perennial usually grown as a half hardy annual by gardeners. Height: 20 to 80 inches (50 to 200 cm). Native: Tropical Africa, Asia, Australasia.
Growing Region: Zones 5 to 10. As a perennial in zones 10. Flowers: Late spring through to early autumn. Flower Details: Inconspicuous spikes, purple, pale blue or violet. Grown for its attractive leaves. Foliage: Green, pink, red, black yellow: variegated leaves.
Sow Outside: Surface. Following last frost in warm areas. Spacing: 6 to to 16 inches (15 to 40 cm). Sow Inside: Germination time: one to three weeks in the light. Temperature 65 to 70°F (18 to 21°C). Two or three months in advance. Transplant outdoors when minimum temperature is not below 45°F (7°C).
Requirements: Full Shade or light shade. Most soils. Rich loam. Moist soil. Monthly feed with fertilizer rich in nitrogen. Pinch tips. Regular watering. Propagate by stem or leaf cuttings in late summer or autumn.
Family: Lamiaceae. Miscellaneous: The Coleus genus is now split between the Solenostemon and Plectranthus genera.
How to Grow Painted Nettle and other Coleus species
It is easiest to start the seedlings of genus plants indoors. They should be started about three months before they are due to be put out.
They should be sown onto the surface and grown in the light at about 18 to 24 degrees Centigrade 64 to 75°F).
They should take around two to three weeks to germinate.
Once seedlings of Painted nettles are established, they should be transplanted at about 20 cm (8 inches; Dwarfs) or 40 cm (16 inches; taller varieties) apart in mid spring, when there is no chance of a frost.
Ideally they should be grown in a shady area that has a moist loamy soil.
Caring for Coleus in the Garden
It is best to pinch back juvenile plants to promote branching.
Coleus should be watered in dry spells. and requires a high nitrogen fertilizer once a month.
Cuttings can be took in the late summer or autumn.