Propagating Pearl Grass (Micranthemum) from Cuttings

Multiply bright-green Pearl Grass by cutting and replanting the tops; with strong light and CO2 the bushy stems spread densely into a low carpet or midground bush.

Overview

Pearl Grass is a small Micranthemum plant in the family Linderniaceae, sold widely in aquascaping as 'pearlweed'. It is a low, subaquatic grower of roughly 5–20 cm with creeping stems, ascending branches and tiny opposite leaves only a few millimetres long. Trimmed low it becomes a bright-green groundcover; left taller it makes a soft midground bush.

Propagation Method (Cuttings)

Because the stems creep and branch, Pearl Grass is propagated simply by cutting and replanting the tops. Each cut top becomes a new plant, while the remaining base branches out, so repeated topping spreads it densely across the substrate.

Step-by-Step

Select healthy, branching stems with bright tiny leaves.
Cut the top 5–10 cm with sharp scissors.
Strip the small leaves from the lowest 1–2 cm.
Push the bare base into the substrate next to the parent.
Repeat topping to widen the patch into a carpet.

Conditions for Healthy Growth

Pearl Grass thrives with strong light and CO2, which keep the tiny leaves close-set and the carpet low and dense; in weaker light it stretches upward and thins. Provide rich nutrients in soft, slightly acidic water to match its fast, hungry growth.

Light: high, to keep the carpet low and compact.
CO2: required for dense, bushy spread.
Temperature: roughly 22–28 °C, soft to moderately hard water.
Nutrients: high demand — dose water column and substrate.

Trimming & Maintenance

Trim roughly every two weeks once established. Frequent topping keeps the stand low and bushy and continuously yields cuttings to replant, so trimming and propagation go hand in hand. Replant the best tops and remove shaded lower growth to prevent the carpet lifting off the substrate.

Common Challenges

Stretching and thinning under low light — raise light or CO2.
Lower layers shading out and detaching as the carpet thickens.
Slow spread if nutrients are lacking for this hungry grower.
Confusion over the trade name, though care is the same regardless of species.