The Narrow leaf Ludwigia needs high levels of lighting to reach its potential, says George Farmer.
Scientific name: Ludwigia arcuata
Common name: Narrow leaf ludwigia
Family: Onagraceae
Origin: North America
Maximum height: 50cm/20”+
Width of each stem: 3-5cm/1.2-2”
Temperature: 20-28°C/68-82°F
Hardness: Very soft to medium
pH: 5.5-8
Light demands: Medium
Growth rate: Medium
Nutrient demands: Easy
What is it?
Ludwigia arcuata is a popular stem plant used to add colour. However, it requires high levels of lighting and ideal nutrients to reach its bright red potential.
The colour of the stems and leaves depend largely on the intensity of lighting you may use. In lower lighting it will remain green, turning to yellow, then orange, then red as lighting intensity increases.
As with a lot of pigmented stem plants, nutrient levels also influence colour. Aquariums with low levels of nitrogen in the water column may see a deeper red. Care should be taken with CO2 in very brightly lit tanks to ensure no nutrient deficiencies can occur, leading to deformed or poor growth.
Growth is slower than for many stem plants, making it easier to maintain. Pruning the tops off the stems will result in two new shoots emerging from the node. Repeating this process over time will result in the bushy effect that many growers desire.
Lower portions of stems can look unsightly, so plant them behind suitable planting or décor.
How to grow it
After purchasing, separate each stem carefully and plant into the substrate using tweezers. Plant in groups of two or three stems, or individually. A nutrient-rich substrate and water column will improve and promote growth, as will CO2 injection.
A typical aquarium will require a minimum of two T5 tubes with reflectors in order to grow this plant effectively.
This article was first published in the December 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.