Propagating Hydrocotyle vulgaris (Marsh Pennywort)

How to propagate marsh pennywort by dividing its long creeping runners and rhizome, then replanting the round-leaved sections to spread a fast carpet.

Overview

Hydrocotyle vulgaris, the marsh pennywort, is a creeping wetland perennial reaching only 5 to 20 cm in height. It produces numerous creeping offshoots up to one metre long that spread horizontally across wet substrate. Its hallmark is the serrated, rounded, shield-shaped (peltate) leaf, up to 4 cm across, with the petiole joining at the centre of the leaf underside, giving an umbrella-like look.

In the aquarium it behaves as a trailing, medium-growth plant. Because it spreads by horizontal runners rather than vertical stems, it is multiplied by dividing those runners, not by topping cuttings.

Propagation Method

The plant reproduces vegetatively through its creeping offshoots (runners and rhizome). Each runner roots at its nodes and sends up new leaves, so a single plant becomes a colony. To propagate, you simply divide an established runner into rooted sections and replant them. Flowers exist but rarely bloom, so seed is not a practical route in cultivation.

Step-by-Step

1. Choose a healthy parent with several long creeping runners trailing across the substrate.
2. Trace a runner and identify nodes where roots and new leaves have formed.
3. Cut the runner between nodes into sections, each carrying at least one rooted node and a few leaves.
4. Replant each section into moist or submerged substrate, pressing the rooted node gently into place.
5. Keep new sections in position; the runners will re-anchor and send out fresh offshoots within weeks.

Conditions for Healthy Growth

Marsh pennywort thrives in wet places such as wetlands, marshes and swamps, and tolerates mud at a pond edge in up to a few centimetres of stagnant water. It prefers reliably moist humus in full sun to part shade and grows well in coldwater and pond setups. In the aquarium it accepts medium light and does not require CO2.

Maintenance

As a fast spreader it needs regular trimming, roughly every couple of weeks, to keep it low and dense and to stop it overrunning neighbours. Routinely tucking stray runners back into position maintains a tidy carpet, and trimmings double as ready-made propagation material.

Common Challenges

Despite its aquatic habit, over-watering of emersed plants can still cause root rot, so emersed pots should drain. Runners can spread aggressively beyond their intended zone, and in low light the trailing growth becomes leggy with longer petioles. Regular division and trimming keep both problems in check.