Pogostemon helferi – Care Guide

Pogostemon helferi, often called "Downoi" (Thai for “little star”), is a unique and eye-catching aquatic plant that's a favorite among aquascapers for its curly, compact, star-shaped leaves and vivid green coloration. Despite its exotic look, it can thrive in both beginner and advanced setups with proper care.

🌿 Overview

• Common Name: Downoi

• Scientific Name: Pogostemon helferi

• Origin: Thailand and Myanmar (found growing submerged along riverbanks)

• Type: Stem plant (but looks like a rosette)

• Growth: Compact, bushy, star-like pattern

• Height: 2–10 cm (0.8–4 inches)

• Placement: Foreground or midground in nano tanks

💡 Care Requirements

🔆 Lighting

• Medium to high lighting is best for compact growth and rich green color

• Under low light, it may grow leggy or lose its star-shaped structure

💨 CO₂

• Highly recommended for lush growth and to prevent melting or die-off

• Can survive without CO₂ but may grow slowly and become less compact

💧 Water Parameters

• Temperature: 22–28°C (72–82°F)

• pH: 6.0–7.5

• Hardness: Soft to moderately hard water

• Flow: Moderate flow mimics its natural habitat

🧪 Nutrients

• Nutrient-rich substrate or root tabs recommended

• Benefits from liquid fertilizers, especially those with iron and potassium

✂️ Maintenance & Propagation

• Growth Rate: Moderate to fast (in high light & CO₂)

• Trimming: Regular trimming keeps it low and compact

• Propagation:

  • Can be trimmed and replanted via side shoots or cuttings

  • Sends out runners or forms bushy clusters if happy

🪴 Aquascaping Tips

• Excellent for foreground carpets or creating lush borders around hardscape

• Contrasts beautifully with fine-leaf plants like Hemianthus callitrichoides or Eleocharis

• Looks especially striking against dark substrates or between rocks in Iwagumi layouts