Star Duckweed care guide
Star Duckweed (Lemna trisulca) — low light, 18-26 °C, pH 6-8, no CO2.
Compiled by Aquairi from published sources · Published · Updated
Overview
Star Duckweed (Lemna trisulca) is an aquatic plant of the family Araceae, listed in the Aquairi knowledge base as a beginner-level species. It is typically grown under low light and without obligatory CO2 injection on any substrate. Submerged duckweed forming chains of small star-shaped fronds. Less invasive than Lemna minor and grows under the surface; useful for shrimp and fry tanks as cover and biofilm host.
Taxonomy
- Family: Araceae
- Genus: Lemna
- Scientific name: Lemna trisulca
Habitat
Lemna is a genus of minute free-floating plants (Araceae, duckweed subfamily) of still and slow fresh waters worldwide; each plant is a tiny flat frond with one or more dangling roots. In the Aquairi knowledge base, populations associated with this form are recorded from Cosmopolitan.
Growth requirements
- Lighting: low
- CO2: not required
- Temperature: 18-26 °C (64-79 °F)
- pH: 6-8
- GH: 3-16 °dGH
- Substrate: any
- Maximum height: 2 cm
- Growth rate: medium
- Recommended placement: floating
Placement
A floating plant that quickly carpets the surface, shading the water column and stripping excess nutrients. In the Aquairi knowledge base this form is recommended for the floating layer under low light and without obligatory CO2 injection, using any substrate.
Propagation
Reproduces by budding, with daughter fronds splitting off the parent; under good conditions the population can double within days. Documented propagation techniques for this entry include: adventitious plantlets on flower stalks.
Common issues
Explosive growth blocks light and gas exchange and is hard to remove once established; regular skimming keeps the surface open.
Propagating Lemna trisulca (Star Duckweed)
Overview
Lemna trisulca, the star or ivy-leaved duckweed, is an aquatic plant of the arum family (Araceae). Its fronds are oblong-lanceolate, up to about 14 mm long, blunt at one end and tapering to a tail-like stalk at the other. Unlike most duckweeds, many fronds stay connected to each other at once, forming branching, star-shaped chains.
Also unlike its surface-floating relatives, it normally grows submerged, just below the water surface, and only rises to float when flowering or fruiting. This makes it a useful low-key cover and biofilm host for shrimp and fry tanks.
Propagation Method
Duckweeds grow mainly by vegetative reproduction: two daughter plants bud off from the parent frond. Lemna trisulca multiplies the same way, through frond budding and division, which lets it colonise new water very rapidly. Simply dividing the chains gives you new plants — no flowers or seeds are needed.
Step-by-Step
- Scoop out a healthy chain of interconnected star-shaped fronds.
- Pinch or pull the chain apart into smaller clusters; each cluster with a few fronds will bud and grow on.
- Place the divided clusters into the destination tank, letting them settle just below the surface.
- Keep surface flow gentle so the submersed fronds are not blown into a single corner.
- Within days, fronds bud daughter plants and the colony re-establishes.
Conditions for Healthy Growth
- Lighting: low light is sufficient.
- CO2: not required.
- Temperature: an optimal duckweed range of roughly 20–28 °C suits it well.
- pH: tolerates a wide range, with better growth around pH 6.5–7.5.
- Nutrients: a modest, low nutrient demand drawn from the water column.
Maintenance
Because it can spread fast, scoop out surplus fronds regularly to keep the colony at the size you want and to stop it shading other plants. Removed clusters are ready-to-use propagation stock or a protein-rich snack for fish and shrimp.
Common Challenges
- Runaway spread: rapid budding can overrun a tank — thin it on a routine schedule.
- Mixing with surface duckweed: keep it separate from floating Lemna minor, which is harder to remove once mixed in.
- Drifting into corners: surface or filter flow can pile the submersed chains up; ease the current for even coverage.