Species guide
Hygrophila polysperma Care Guide (Fast Stem)
Aquatic plant
Hygrophila polysperma is the forgiving fast stem for beginners. It grows emersed or submerged, roots from every node, and fills a low-tech tank if you pinch tops instead of letting it shade itself.
- Easy stem
- Fast
- Pinch & replant
- Low–medium light
Quick facts
| Light | Low–medium; stronger light = tighter internodes + possible pink |
|---|---|
| CO₂ | Optional — speeds growth, not required |
| Temp | 20–28 °C |
| Planting | Group stems 2–3 cm apart; substrate or weights |
| Trim | Pinch tops weekly; replant cuttings |
| Fert | Lean all-in-one liquid; root tabs optional |
| Invasiveness | Restricted in some US states — check local law |
| Height | 20–50 cm easily |
Overview
Polysperma is a stem you manage with scissors, not a set-and-forget rosette. If lower leaves melt, the stand is too thick or the light too weak — not “bad genetics.”
Compare stems: Rotala rotundifolia (wants more light/CO₂ for color) · water wisteria (broader leaf, still easy). Easy hardscape plants: Anubias · Java fern. Triangle: light/CO₂/fert.
How to grow it
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Step 1
Plant a group, not one stick
5–9 stems midground. Space so light hits lower nodes.
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Step 2
Pinch before it hits the surface hard
Toppings become new stems. Replant immediately or float 2 days then plant.
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Step 3
Lean liquid fert 2–3×/week
It is a nutrient hog if light is medium. Yellow new growth → more N or Fe.
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Step 4
Thin the stand monthly
Pull the oldest woody bottoms. Dense mats invite BBA and GSA.
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Step 5
Check local rules
H. polysperma is invasive in parts of the US. Do not dump in waterways.
Common problems
Lower leaves drop, tops fine
Why: Self-shading / low light at the base.
Fix: Pinch, replant tops, thin. Raise light or shorten height.
Leggy long internodes
Why: Not enough light.
Fix: Move up or add a real planted LED. See light tool.
BBA on old leaves
Why: Organic film + excess light hours.
Fix: Trim old leaves; 6–7 h photoperiod; more flow.
Melts after high-tech upgrade
Why: CO₂/light jump without fert.
Fix: Match fert to new light. Read low vs high-tech.
Tank mates
- Peaceful community: neons, guppies, corys.
- Bettas use the leaves as rest perches.
- Shrimp: yes. Dense stems hide shrimplets — tank mates.
- Goldfish will shred it. Skip.
Gear for this species
Landen Aqua Soil Substrate for Natural Planted Aquarium, Plant or Shrimp Stratum, Clay Gravel and Stable Porous Substrate for Freshwater Aquarium, Black Color 40lbs
Substrate vàng chuẩn Iwagumi / Nature Aquarium.
API Root Tabs Freshwater Aquarium Plant Fertilizer 10-Count Box
Viên phân gốc API — cây ăn rễ, bổ sung macro cho nền.
Best beginner aquarium plants — Pinch polysperma or it becomes a shade tree
FAQ
Is polysperma illegal where I live?
Some US states restrict it. Check before you buy or trade.
Do I need CO₂?
No for green growth. CO₂ + stronger light makes tighter, possibly pinker tops.
Can I leave cuttings floating?
Short term yes. Plant them or they get messy and shade everything.
Why no side shoots?
Not pinching. Tops suppress sides until you cut.
Good with Amazon sword?
Yes — sword mid/back, hygro mid. Watch the sword’s shade.
Differs from water wisteria?
Wisteria (H. difformis) has more divided leaves. Same pinch habit. See wisteria guide.
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