Propagating Riccia fluitans (Crystalwort) by Division

How to multiply the floating liverwort Riccia fluitans by splitting the clump into pieces, and how to tie it under mesh for a pearling carpet or simply let it float.

Overview

Riccia fluitans, the floating crystalwort, is a liverwort that has no true roots. It normally grows quickly at the surface, forming dense mats of bright-green branching fronds. It naturally floats but can be attached to underwater objects such as logs and rocks, where aquascapers grow it as a carpet. Made famous in planted-tank aquascaping, it pearls with oxygen bubbles under strong light.

Propagation Method

Propagation is by simple division: any single branch or antler bud can grow into a large colony in proper conditions. You split a healthy clump into smaller pieces, and each fragment continues to spread on its own.

Step-by-Step

Lift a healthy clump and pull or cut it into several smaller pieces.
To carpet: spread a thin layer of pieces over a stone or wood and secure it with plastic mesh or netting.
To float: simply place the pieces on the surface and let them form a mat.
Trim regularly so the mat stays thin and light can reach the lower fronds.
As the colony thickens, lift and divide it again to start new sections.

Conditions for Healthy Growth

Crystalwort thrives in bright light; kept about two to three inches below an ordinary fluorescent bulb, or in a pond in full sunlight, it forms thick mats. Strong light is what drives the prized pearling. As a fast grower it appreciates good nutrients and the added CO2 typical of carpet setups.

Maintenance

Trim the mat often to keep it dense and prevent the lower layer from dying off and detaching. Thin out excess growth so the carpet does not lift away from its mesh, and remove drifting fragments if you want to keep the layout tidy.

Common Challenges

Hair algae: crystalwort is easily overtaken by hair algae, so keep light and nutrients balanced.
Crowding by duckweed: it is generally incompatible with duckweeds, which can crowd it out.
Carpet detaching: an overgrown mat traps oxygen and lifts off the mesh; trim it thin.
Sparse growth: usually means light is too weak to support a dense carpet.