Ludwigia repens is the red stem plant to start with. Tropica rates the ‘Rubin’ variety easy, with a medium demand for light and a low demand for CO2, so the colour does not depend on a pressurised system. Light is what decides how red it goes.
Tropica rates the ‘Rubin’ variety
Worth knowing before you shop. Tropica lists no plain Ludwigia repens, only the variety ‘Rubin’, so the figures on this page are theirs for that plant. Tropica describes it as a variety of Ludwigia repens from North America with striking dark red leaves and stalk, with stems from 20 to 50 cm and 4 to 6 cm wide.
Light makes the red
Tropica says the plant has few demands, but that if light is insufficient the lower leaves tend to fall off, and that in strong light the colour becomes more intense. Bare lower stems are the first sign that your light is not reaching far enough down.
What it needs
| Requirement | Ludwigia repens ‘Rubin’ |
|---|---|
| Light demand | Medium |
| CO2 demand | Low |
| Difficulty | Easy |
| Growth rate | Medium |
| Placement | Stem, background |
Plant it in groups and keep cutting
Tropica’s advice is to plant it in large groups to enhance the decorative effect and to prune regularly to encourage bushy growth. That is the same trim-and-replant cycle Rotala runs on, and the discipline behind the Dutch style, where rows of contrasting colour carry the layout.
A red group reads strongest against plain green neighbours, so give it space rather than scattering single stems through the tank.
Ludwigia repens questions
Does Ludwigia repens need CO2?
No. Tropica rates the CO2 demand of ‘Rubin’ as low. Added CO2 is not what makes it red, light is.
Why are the lower leaves falling off my Ludwigia?
Usually light. Tropica says that if light is insufficient, the lower leaves tend to fall off. Thinning the stems above so light reaches down, or raising the light level, is the fix.
How do you make Ludwigia repens red?
Give it stronger light. Tropica says the colour becomes more intense in strong light, and rates the plant’s own light demand as medium.
Sources: Tropica, Ludwigia repens ‘Rubin’.