This strikingly-coloured dark red plant was imported by the Danish aquatic plant nursery Tropica under the name Ludwigia repens 'Rubin'. It is also known as Ludwigia sp. "wine red". Recent research showed that it is not a L. repens variety but a relative of L. glandulosa, and probably a hybrid. For this reason, it is also called Ludwigia aff. glandulosa (Kramer 2006; aff. = affinis = "related, close") or Ludwigia "Rubin" (Kasselmann 2010). Some nurseries erroneously carry the plant as L. glandulosa or "L. glandiosa" (distrinction from true L. glandulosa: see below).
The leaf form of Ludwigia "Rubin" is quite similar to that of L. repens, and its growth habit is also comparable. However, whereas L. repens always has oppsite leaves (2 leaves per node), the shoot parts of L. "Rubin" have opposite as well as alternate leaves (1 leaf per node) at irregular intervals. Ludwigia glandulos, which has a similar wine-red colour, always has alternate leaves, a narrower lanceolate leaf form as well as more strictly upright almost unramified submersed stems.
Like the more common L. repens, L. "Rubin" is easy to keep and does not pose any special demands on the conditions it is cultivated in. However, it only assumes its characteristic deep read colour under lots of light (0.5 watts per litre and over) and a good iron supply. Ludwigia "Rubin" throws many roots on its nodes, which can be removed without problems, though. The plant is a little susceptible when transported, but recovers easily from the damages caused given that it is provided with good growing conditions.
Propagation is as easy as for all stem plants. L. "Rubin" forms lateral shoots on a regular basis, which can be cut off and re-planted, as well as the top shoot.
Ludwigia "Rubin" is one of the darkest red plants, which makes it a true eyecatcher in any aquarium layout. A small group, positioned in the middle ground, with some green plants as a backdrop, will provide the onlooker with a beautiful focal point. Microsorum pteropus "Narrow Leaf" or Hygrophila balsamica used as neighbouring plants bring out its colours especially well.
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