Ludwigia repens

Overview

Ludwigia repens is one of the most forgiving stem plants you can start with. Its rounded leaves are green on top and reddish to copper underneath, and under good lighting the red spreads across the whole plant. It is native to the southern United States, Mexico and the Caribbean, where it grows in ponds, ditches and along stream banks, often partly emersed.

Hobbyists like it because it adds color without expensive gear: it does fine in tanks without CO2, grows quickly and soaks up nutrients, which helps keep algae in check in newly set-up aquariums. Cultivars such as 'Rubin' and 'Super Red' are redder but a bit more demanding. It makes a great first red plant for beginners.

Care and tank setup

Place it in the midground or background, in groups of stems spaced about an inch apart so light reaches the lower leaves. In shallow tanks it can serve as a background plant.

• Light: medium. In low light it survives but turns green, gets leggy and drops its lower leaves. Strong light brings out the red and keeps it compact.
• CO2: optional. It grows well without it; with CO2, color and density improve a lot.
• Substrate: any fine gravel or sand works if you fertilize; an aquasoil or root tabs help.
• Planting: strip the leaves from the bottom 1-1.5 inches and plant each stem individually with tweezers, rather than in bunches tied with a lead weight.

Common mistake: planting it in the shade of floaters or taller plants. Aerial roots and bare stems mean it needs more light. Large herbivorous fish may nibble it.

Fertilizing and trimming

Because it grows fast, it is a heavy feeder: a weekly comprehensive liquid fertilizer with iron keeps the color; pale new leaves usually point to a lack of iron or nitrate. Trim when stems reach the surface: cut off the top and replant it, since the remaining base regrows slowly and looks scruffier. Every few months, rebuild the group from healthy tops.

Propagation

It propagates easily from cuttings: snip 3-4 inch tops, strip the lower leaves and plant them; they root within days. The trimmed base also sends out side shoots. Out of water it develops an emersed form with glossier leaves. Never dump trimmings into streams, ponds or drains: outside its native range it can become invasive.

Recommended equipment

What you need to keep the Ludwigia repens healthy, checked against Amazon stock.