Downoi
Pogostemon helferi
Also known asLittle star · Dao noi · Daonoi
Water parameters
Light and nutrients
Substrate type: nutrient rich. Propagation: lateral shoots.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| Aquasoil (ADA Amazonia) | lowers pH | very high |
| Mineralized clay substrate (Seachem Fluorite) | neutral / inert | moderate |
| Dirted tank (mineralized topsoil) (DIY soil substrate) | slightly acidic | very high |
With fish
Origin and habitat
A small star-rosette plant of the mint family, Lamiaceae, Pogostemon helferi, native from northeastern India through Indo-China, distributed across Myanmar and western Thailand with its type locality in Kanchanaburi, Thailand, on stream banks and in shallow seasonally-flooded water. Thai collectors named it dao noi, 'little star', for its rosettes of wavy-edged bright-green leaves that emerge in a zigzag, giving a ruffled, layered look unlike any other aquarium plant. Rosettes are roughly 3–8 cm across and a few centimetres tall, suiting foreground to midground use. Found for the hobby in the early 2000s along the Thailand-Myanmar border, downoi became a Nature Aquarium favourite and featured early in ADA aquascaping work, making it a classic species.
Care notes
Moderate to demanding. It wants medium to high light and really needs stable CO2, without which, or in low light, the rosettes stretch out and lose the compact star shape that is the whole point. It is a strong root feeder with a sizeable root system, so a nutrient-rich substrate such as aquasoil plus root tabs gives the best results, and iron and potassium matter especially, with deficiency showing as pale or yellow new leaves and loss of the ruffled texture, though it recovers quickly if caught early. Plant individual rosettes a few centimetres apart; growth is moderate, the plant throwing new rosettes on short runners into an overlapping cluster of stars, and it also makes side shoots and leaf-axil plantlets. Keep it around 22–28°C in soft to moderately hard water. The zigzag, ruffled leaves catch light at many angles for a complex, textured foreground. Propagate by separating daughter rosettes or replanting cut tops. It is an ornamental, not a crop, so it is unsuited to media-bed aquaponics or hydroponics.