Propagating Rotala rotundifolia 'H'ra'

How to propagate the red cultivar Rotala rotundifolia 'H'ra' by topping and replanting stem cuttings, and how to bring out its wine-red color.

Overview

Rotala 'H'ra' is a selection of Rotala rotundifolia, a flowering stem plant of the family Lythraceae native to rice paddies and wet places across India, China, Taiwan, Thailand, Laos and Vietnam. Submerged, the parent species carries narrow, lanceolate leaves, and 'H'ra' pushes this further with especially fine foliage that turns deep orange to wine-red under intense light.

Like its parent it is propagated by cuttings and grows fast, so a few stems quickly become a full bush you can divide repeatedly.

Propagation Method

The standard method is topping: cut the upper portion of a healthy stem and replant the cut top as a new plant. The trimmed base remains rooted and branches into multiple side shoots, so each topping multiplies the bush. Replanting the cut tops, rather than discarding them, is what makes Rotala so easy to propagate.

Step-by-Step

Choose firm, well-coloured stems and cut the top 5-10 cm with sharp scissors.
Strip the lowest pair of leaves from each cutting to expose a clean node.
Dib the cuttings into the substrate so the bare node is buried.
Leave the rooted bases in place to branch into new shoots.
Keep light, CO2 and nutrients high while the cuttings root and colour up.
Repeat the topping cycle as the bush regrows to thicken the stand.

Conditions for Healthy Growth

Rotala rotundifolia is undemanding but strongly light-dependent: insufficient illumination causes lower leaf loss and keeps the plant green. To earn the wine-red colour of 'H'ra' you need plenty of light together with nutrients and CO2, which also drive the creeping growth via side shoots. A lean nitrate level intensifies the red.

Light: high, to trigger red coloration and dense growth.
CO2: injected, for fast healthy growth and best colour.
Nutrients: full dosing but lean on nitrate to deepen red tones.
Substrate: a nutrient-rich aquasoil supports fast rooting.

Trimming & Maintenance

This is a fast grower that responds well to frequent trimming. Regular topping keeps the stand dense and the colourful tops near the light; the cut tops double as propagation material. Thin out overcrowded stems so light reaches the lower leaves and they do not shed.

Common Challenges

The usual complaints are leggy green stems and bare lower stalks, both symptoms of too little light. Raise light, add CO2 and keep nitrate lean to restore the red, and trim regularly so the lower leaves are not shaded out.