TankBud

Star duckweed

Lemna trisulca

Also known as Ivy duckweed, Ivy-leaved duckweed, Narrow-leaf duckweed, Star duckmeat

FreshwaterFloatingDivisionFragmentation

Star duckweed (Lemna trisulca)
Christian Fischer · CC BY-SA 3.0

Care at a glance

Light
Low light
CO2
No CO₂ needed
Temperature
50–79°F
10–26°C
Max height
0.4 in
1 cm
Growth rate
Medium
Placement
Floating
Type
Floating
pH
6.0–8.0
Hardness
2–18 dGH
Spread
7.9 in (20 cm)
Nutrient uptake
Water column
Growth region
Submersed or emersed
Difficulty
Easy
Family
Araceae
Origin
A cool water duckweed of temperate ponds and slow streams across the Northern Hemisphere, drifting just under the surface rather than on top of it.

Overview

Star duckweed is an easy floating plant that gives shrimp and fry a soft, sheltering thicket.

Did you know

Star duckweed rises to the top of the water only to flower. The rest of the time its chains tangle into loose cushions that drift midwater.

Caring for star duckweed

Add star duckweed to the tank and let it drift, since it needs no substrate. Low light is enough, and it grows without CO2. It feeds from the water column, so any fertilizer should go in as a liquid.

It tolerates cool water well and takes 50 to 79°F (10 to 26°C). It grows at a medium pace and builds up into cushions over time. It is far less aggressive than common duckweed and will not choke the surface.

Thin it if it gets thick enough to shade the plants beneath. Pieces that break off keep growing, so pulling a clump apart is all it takes to propagate it.

Good to know

Star duckweed is one of the few duckweeds that grows submerged. Its translucent, toothed fronds stay joined in branching, ivy-like chains rather than floating singly. It sits in the arum family, the same broad group as anubias and philodendron.

In the wild

Star duckweed is a cool-water duckweed of temperate ponds and slow streams across the Northern Hemisphere. Unlike the duckweeds that coat the surface, it hangs just below the waterline.

Common questions

Does star duckweed need to be planted in the substrate?

No. Star duckweed floats in chains just below the surface and takes its nutrients from the water.

Does star duckweed need CO2?

No. Star duckweed grows well without added CO2 and suits a low-tech tank.

How much light does star duckweed need?

Star duckweed is a low-light plant, and the light that comes with a standard tank kit is enough for it.

How do you propagate star duckweed?

Star duckweed propagates by division and fragmentation. Each frond buds off new ones, and the chains build into a loose tangle below the surface. Pieces that break off keep growing, so pulling a clump apart spreads it.

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