Propagating Cryptocoryne blassii: Runners and Rhizome Division

A propagation guide for Cryptocoryne cordata var. blassii, a broad-leaf rosette crypt, covering stolon runners, rhizome division, and managing crypt melt.

Overview

Cryptocoryne blassii is treated as Cryptocoryne cordata var. blassii, a large broad-leaf rosette crypt in the family Araceae. Like all members of the genus it is naturally distributed across tropical Southeast Asia, where the cordata complex includes several regional varieties. It is a slow rosette plant prized for its dark upper leaf surface and reddish underside, and it reproduces vegetatively rather than from cuttings.

Propagation Method (Runners and Division)

Propagation is by runners (stolons): horizontal underground shoots that travel through the substrate and raise daughter rosettes nearby. A well-established clump can also be lifted and divided through its rhizome so that each section becomes an independent plant. Both methods are slow and reward patience.

Step-by-Step

Let the mother plant settle and send out stolons bearing daughter rosettes.
Expose the runner in the substrate connecting mother to daughter.
Sever the runner once the daughter has its own roots and a few leaves.
To divide the rhizome, lift the clump and split it so each piece keeps roots and foliage.
Replant in nutrient-rich substrate with the crown sitting above the soil.

Conditions for Healthy Growth

As a low-demand crypt it tolerates low light and does not require CO2. Being a root feeder, it performs best in a nutrient-rich substrate. The cordata group inhabits streams and seasonally inundated forest pools, so stable, gently moving water suits it. Place this broad-leaf form in the midground where its colours show.

Maintenance

Keep nitrate low with regular water changes, prune away spent leaves, and otherwise leave the plant undisturbed. Slow growth means it rarely needs thinning; let the runners expand the colony naturally.

Common Challenges

Crypt melt is the first thing to expect: after transplanting, the plant may drop all its leaves in response to rapid environmental change, the shift from emersed nursery growth to submersed conditions, or nitrate buildup. Leave the rhizome in place; it generally regrows fresh submersed leaves once the tank stabilises, often within about a month.