Coleus forskohlii: Ancient Ayurvedic Herb, Modern Garden Gem

Coleus (Solenostemon scutellarioides) has dazzled gardeners since Victorian times with its kaleidoscopic foliage. But beyond the ornamental hybrids lie edible species with deep roots in Ayurvedic medicine—particularly Coleus forskohlii, a source of forskolin, a compound studied for heart, lung, and metabolic health.

Taxonomy Update

The genus Coleus was reclassified to Solenostemon in 2006, though "coleus" remains the common name. Two edible species stand out:

• Solenostemon rotundifolius (syn. Coleus rotundifolius, Plectranthus rotundifolius): Grown for its small, spicy, potato-like tubers (Hausa potato, Madagascar potato, koorka).
• Coleus forskohlii: Ayurvedic herb used for 3,000+ years; roots contain forskolin.

Insights from a Coleus Expert

I interviewed Ray Rogers, author of Coleus: Rainbow Foliage for Containers and Gardens.

Favorite coleus? 'Alabama Sunset'—its colors shift from pink to green to burgundy. One of the ten most-photographed on Dave's Garden.

Your garden? Formal, small; most coleus grown at Atlock Farm nursery (Somerset, NJ).

What's a "sport"? A cellular mutation creating a new color pattern. 'Freckles' sported 'Sedona' (rusty orange, ColorBlaze™ series, 2003).

Overwintering indoors? Tricky. Needs warmth, bright sun, careful watering (not too much). Greenhouse ideal. Cut flower spikes to prevent seeding. Propagate via root cuttings to save favorites.

Edible species knowledge? "Not really... I don't grow them." —Ray Rogers

Coleus forskohlii: The Ayurvedic Powerhouse

Named for Swedish naturalist Peter Forsskål, C. forskohlii thrives in warm subtropical regions (India, Gujarat, Karnataka, Tamil Nadu). ~2,500 tonnes cultivated annually by local/contract farmers—drought-tolerant, low-input. Roots used in medicines, pickles, and supplements. Gaia Herbs (Brevard, NC) imports whole-plant material from India; their product isn't standardized beyond heavy-metal/pesticide/microbial testing, implying benefits beyond isolated forskolin.

Traditional & Researched Benefits

In Ayurveda (Sanskrit: Makandi), used for heart, lung, GI, immune support; hypertension, asthma, eczema, glaucoma, IBS, menstrual cramps; may stimulate cAMP (cyclic adenosine monophosphate), linked to weight loss. Forskolin activates adenylyl cyclase → ↑cAMP → complex cellular effects. Thousands of studies explore forskolin as a research tool; clinical applications evolving.

Nutrition & Safety

• Primary nutrient: carbohydrates (energy). Tubers provide fiber.
• Recent study (Rasineni et al. 2008): High polyphenols, flavones, flavonols, antioxidant activity in three coleus species including C. forskohlii.
• USDA vitamin/mineral data unavailable.
• Caution: Consult a healthcare practitioner before use, especially if on BP meds or prescriptions. Forskolin's wide-ranging effects warrant caution.

Solenostemon rotundifolius: The "Coleus Potato"

Prostrate habit; clusters of small, round, brown tubers (150–200 days). Flavor: slightly spicy, pleasant, moist, grainy. Foliage: classic coleus—pink veining, burgundy, chartreuse edges. Known as Hausa potato, Sudan potato, ratala, koorka.

Growing Edible Coleus

Plants/tubers are hard to source. If you find them, treat as tender perennials: warm, sunny, well-drained soil. A unique challenge for adventurous gardeners!

References

1. Rogers, Coleus: Rainbow Foliage..., Timber Press 2008, p.17
2. OSU Food Resource / Hawkes, A World of Vegetable Cookery 1968
3. FAO Ecocrop: Solenostemon rotundifolius
4. Prabu, The Hindu, Dec 2008
5. Rasineni et al., J. Med. Plants Res. 2(10):285–291, 2008

Photos: Thumbnail forskolin (public domain); 'Sedona' © DG member Slyperso1; others © DG member DaleTheGardener. All used with permission.