Source: Wikimedia Commons
Downoi
IntermediatePogostemon helferi
A beautiful foreground-midground plant with star-shaped wavy leaves. A unique aquatic plant distributed from eastern India to Thailand.
Overview
Pogostemon helferi is an aquatic plant in the family Lamiaceae native to streams stretching from eastern India through Myanmar to Thailand, where it colonizes shallow, fast-moving streams. It is known locally as 'Downoi' (meaning 'little star' in Thai), a name that perfectly captures the distinctive star-shaped, crinkled leaves that set it apart from virtually every other aquarium plant. Used in foreground to midground positions, its unique leaf architecture provides textural contrast within compositions. Brighter illumination and CO2 injection improve both coloration — healthy specimens achieve a rich, deep green — and growth rate, which is otherwise moderate. It is somewhat sensitive to abrupt changes in water chemistry and benefits significantly from nutrient-rich aquasoil. Discovered and popularized by Thai aquarists, it spread to the global hobby and has since become a sought-after species prized for its botanical uniqueness.
Size of the Downoi
The Downoi grows to 3-10cm.
Temperature & humidity for the Downoi
The ideal temperature for the Downoi is 20〜25℃.
Basic Info
Origin
Eastern India (West Bengal), the eastern Himalayas, Myanmar and Thailand
Lifespan
Perennial
Size
3-10cm
Temperature
15〜28℃
Watering & Fertilizer
Root tabs, CO2
Growing Tips
Lighting
Needs fairly bright lighting. With enough light a healthy plant turns deep green, and its distinctive leaf shape stands out in the fore- to midground.
CO2 & Fertilizer
CO2 injection improves colour and growth. Rely mainly on substrate fertilizer; it grows strongly in a nutrient-rich substrate.
Water Temperature & Quality
Slightly acidic to neutral water is best. It is somewhat sensitive to water changes, so avoid abrupt shifts and prioritize stability.
Substrate & Attachment
It pairs well with aquarium soil and roots well in nutrient-rich soil. Place the plants in the fore- to midground.
Trimming & Propagation
Growth is somewhat slow but the plant spreads steadily. Divide the offshoots from the base and replant them to propagate.
Downoi FAQ
QWhat is the growing difficulty level for Downoi?
Intermediate. A variety suitable for intermediate growers. Requires some cultivation experience and knowledge of environment management. Pay careful attention to temperature and humidity control.
QWhat is the ideal temperature for Downoi?
The ideal temperature for Downoi is 20〜25℃. Avoid sudden temperature changes and maintain a stable environment.
QHow large does Downoi get?
The mature size of Downoi is 3-10cm. This may vary slightly depending on cultivation environment and individual differences.
QHow should I water and fertilize Downoi?
Downoi: watering & fertilizer — Root tabs, CO2. Aim for appropriate frequency and amount.
QWhat is the typical price for Downoi?
The price of Downoi varies significantly by variety, characteristics, size, and lineage. Please check GrowerDirect's price guide for the latest market information.
Last updated: October 2, 2026
References & Sources
Edited & verified by: GrowerDirect Editorial Team
The classifications, regulations, and growing data on this page are created and verified based on the primary information database below.
Taxonomy & Authority
Regulations & Conservation Status
Sources: Ministry of the Environment Designated Invasive Species List (Invasive Species Act) / CITES Appendix II listed plant taxa (family and genus level)
Regulations may change. Always verify the latest information with the relevant authorities.
Related Species
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