Propagating Rotala Rotundifolia 'Singapore': Cuttings Guide

Propagate the small-leaved, pink-topped Singapore form of Rotala rotundifolia by cuttings, with step-by-step topping, lighting, lean nitrate and CO2 advice for a tidy stand.

Overview

Rotala rotundifolia 'Singapore' is a locality form of Rotala rotundifolia (family Lythraceae) with smaller leaves and brighter pink tops. The parent species is a common weed in rice paddies and wet places across India, China, Taiwan, Thailand, Laos and Vietnam and grows both submerged and emersed; the emersed form has rounded leaves while submerged leaves are narrow and lanceolate, and under strong light the leaves can become almost wine red.

As a rotundifolia-group cultivar, 'Singapore' is propagated identically to the parent: by cuttings. It is a well-behaved stem for nature aquascaping, branching readily into a tidy midground bush.

Propagation Method (Cuttings)

Propagation is by cuttings. Removing the apical bud encourages lateral buds to develop along the stem at the internodes, so each topped stem branches and grows bushier. The cut top is replanted as a new plant; the remaining base sends out side shoots from below the cut.

Step-by-Step

1. Choose a vigorous stem with healthy pink tops, at least 10-15 cm tall.
2. Cut the top 5-10 cm using clean, sharp scissors.
3. Strip the lowest 2-3 cm of leaves so they will not rot below the substrate.
4. Plant the bare base into nutrient-rich substrate, leaving room for light between stems.
5. Keep the original base; it will push lateral shoots from the internodes under the cut.
6. Provide adequate light and CO2 so the replanted tops root and color up.

Conditions for Healthy Growth

The parent species is undemanding but requires light to thrive; loss of lower leaves indicates insufficient lighting. Sufficient coloration begins around 80 umols of PAR, with strongest color at 150-200 umols PAR. 'Singapore' shows redder, pinker tops under nitrate limitation: increasing nitrate turns new shoots green/yellow, moderate nitrate gives slightly orange/green shoots, and steep, prolonged nitrate limitation turns leaves dark red. Rotala can grow without CO2 but is harder to keep healthy that way.

Trimming & Maintenance

Trim roughly every 10 days to maintain a dense, even canopy. Topping removes the apical bud and triggers fresh lateral branching, simultaneously multiplying and shaping the plant. Replant the harvested tops to fill in the midground and remove leggy old bases.

Common Challenges

Dropping lower leaves means too little light. Thin stems that branch infrequently indicate low CO2 or nutrients. If the tops stay green instead of pink, nitrate is likely too high. Note that the parent species is often confused with the closely related Rotala indica, distinguished by inflorescence structure.