Ludwigia arcuata has attractive reddish foliage and is easily trimmed to form dense bushes. Tank example above by Thomas McCowan.

Introduction

Ludwigia arcuata is a delicate stem aquatic plant that originates from the US. It is often confused with Ludwigia brevipes, which is similar, but slightly larger with broader leaves. It is also similar to Didiplis diandra which is much harder to grow well. Ludwigia arcuata has attractive orange – reddish leaves and thin stems and leaves.

Ludwigia arcuata is tolerant of a wide range of water parameters and is generally an easy background aquarium plant to grow as long as it receives enough light and nutrients. This stem plant grows much redder with nitrate limitation.

Ludwigia arcuata can be trimmed aggressively. This encourages side shoots to form and the plant can become very bushy. It is quite resilient to being grown densely, and can be pruned for many weeks without requiring replanting. It can be used in aquascaping smaller tanks as mid/background aquarium plants due to its fine texture.

Key success factors

• Sufficient light (medium onwards)
• Avoid extreme water parameters
• Basic fertilization
• CO2 necessary to grow it in good form

Water in this tank is between 9 -11 dKH. Suffice to say, Ludwigia arcuata still grows well.

To learn more CO2 setup, click here.

how to get it redder

• Stronger light (higher PAR values)
• Stronger red/blue light spectrum
• Low nitrates causes it to become significantly redder

This is one of the plants that exhibit much redder colors under nitration limitation – meaning that the plant grows much redder if it is starved for nitrates. Over-do this and the plant will stunt. However, since it is tolerant of much lower nutrient levels than other plants – other plants will usually stunt first.

Trimming allows Ludwigia arcuata to be trimmed into dense bushes. In the tank above, under slight NO3 limitation it appears orange rather than deeper red. Ludwigia arcuata becomes significantly redder under low NO3.

Trimming

Cut off top of plant a few inches below the final desired height. Side shoots will sprout from the remaining bottom portion to fill in the area. As the side shoots form, trim away faster growing shoots that poke above the rest. Over time, you will have a nice contoured bush.

​This stem plant will grow sideways if there is a lot of light and empty space. Planting a bit more densely at the start – with stems about 1.5cm apart, will encourage them to grow more vertically.

Head here to find out how to read PAR values.

Head here to find out how to fine tune light spectrum.