Meet a medicinal coleus with a history that stretches back 3,000 years. Coleus forskohlii is an herb commonly used in traditional Ayurvedic medicine. It first appeared in Sanskrit texts over 3,000 years ago. Local Indian farmers still raise Coleus forskohlii today, selling the harvested roots to local, as well as international markets.
Botanically, Coleus forskohlii is also known as Coleus barbatus or Plectranthus barbatus. It has a host of common names, including forskohlii, makandi or kaffir potato. Like all coleus, it’s a member of the mint family, featuring square stems and leaves arranged in pairs opposite one another along stems.
Unlike ornamental coleus, Coleus forskohlii lacks showy, spectacularly colored leaves. It has plain, bright green leaves and flowers that are blue to lavender. Like its eye-catching coleus cousins, Coleus forskohlii grows best in a soil that’s a mix of fertile garden loam and sand. Its native habitat is mountain slopes in India, Thailand and Nepal, which means it thrives in well-drained soil.
Coleus forskohlii is a perennial in frost-free zones (Zones 10-11) and behaves like a tender perennial in Zone 9. Frost kills stems and leaves, but roots survive. In these frost-prone zones, it’s a good idea to mulch plant crowns in late fall to provide extra protection. It’s tough to find Coleus forskohlii plants or tubers for sale, so if you have a plant, take every precaution to keep it alive. In colder zones, the way to overwinter Coleus forskohlii is to grow it in a container you bring indoors for winter or to take cuttings for rooting.
Grow Coleus forskohlii in full sun in northern regions; provide afternoon shade in warmest zones. Plants are reportedly drought-tolerant once established but grow more evenly and strongly with regular moisture. In containers, water frequently enough to keep Coleus forskohlii from wilting.
Like other coleus, pinching growing tips from stem causes Coleus forskohlii to branch and become bushier. Plants usually grow to about 24 inches tall. Width is somewhat variable depending on how often you pinch plants. You can prune Coleus forskohlii at any point during the growing season to curtail growth. In regions where it behaves as a tender perennial, cut back old stems in spring as new growth appears.
You’ll most likely encounter Coleus forskohlii in health food stores, where extracts drawn from the roots and/or the entire plant are dried and packaged. People seek out Coleus forskohlii for its high polyphenol content. Medical researchers have documented that the active ingredient in Coleus forskohlii roots, forskolin, does lower blood pressure and decrease muscle spasms, such as those that occur with asthma.
Recently Coleus forskohlii is a hot topic because of its purported ability to help burn fat and accelerate weight loss. U.S. medical experts do not believe that the research exists to support using Coleus forskohlii for any specific therapeutic benefit.