Common Ludwigia
Photo by jm1212.
Scientific Name: Ludwigia repens X arcuata
Common Names: Ludwigia, Common Ludwigia, Red Ludwigia
Type: stem
Difficulty: easy
Light Requirement: low is fine for just growth, but for the deepest and brightest colors, upgrade to a brighter light source.
Size: large, in terms of height: will quickly grow to the height of the tank and beyond, and pieces that are double the height of the tank are not uncommon, as they will grow along the surface as well. Width-wise, these are thin plants.
Growth Rate: very fast, even in med-low light. in low light, i.e less than 1 wpg, growth is more moderate.
Origin/Habitat: Original plants from North America namely the Southern US and Mexico, but this plant is a hybrid.
According to jm1212, he originally had his ludwigia under an anemic light; on my 37G tank, the 17 watts of glory only allowed for .46 wpg. Still, the ludwigia grew pretty well. After upgrading to a 65W light that provides 1.76 wpg, the growth of his ludwigia has increased exponentially. In fact, he needs to trim his ludwigia nearly every week to keep it from blocking the light from the shorter ludwigia and other shorter plants in my tank. In addition, he has had stems that were double the height of the tank, and grew along the surface of the water. Ludwigia responds well to Excel and Flourish, so consider them for low-tech ferts.
References/Links:
http://fish.mongabay.com/plants/Ludwigia_arcuata.htm