About the Ludwigia
Species Type: Freshwater Plants
Care Level: Moderate. Require soft to moderately hard water though some species may have a preference, low to medium light, regular fertilization. pH 6.0 to 7.2, GH up to 10 degrees/180ppm.
Origin: United States and Mexico.
Of all the species in the genus Ludwigia, this one is the most easily grown and most successful in aquaria, and is thus the most often seen in the hobby. It adapts to differing water parameters, does well with moderate illumination, and growth is rapid. A nutritious substrate is advantageous, and regular liquid fertilization will result in strong growth. Propagation is via lateral shoots that will appear regularly. The similarity between leaf forms of the various species means that the flowers must be observed to definitely identify them.
There are several growth forms of L. repens available, differing slightly in leaf shape and colouration, but having no taxonomic status (Kasselmann, 2003). This is also the reason why this plant is sometimes seen under the names Ludwigia natans and Ludwigia "mullertii." The species was initially described as Ludwigia repens by Forster in 1771 and this is the valid name. Several botanists subsequently described what they believed was a different species, including Ludwigia natans by Ell in 1821. All the varieties show intermediate forms (Munz, 1965).
Two hybrid species using Ludwigia repens are available, and these, described below, are also good aquarium plants.
Ludwigia palustris X L. repens has reddish foliage and although it will grow under moderate lighting, more intense light will produce stronger growth with better red colouration. The optimum temperature for this hybrid is 23-28C/73-82F. This cultivated hybrid has been observed growing naturally in Mexico (Kasselmann, 2003).
Ludwigia repens X L. arcuata is a cultivated hybrid that grows more rapidly and with even fewer problems that either of the parent species, what is known botanically as heterosis. With moderate light the leaves will be olive green, but under intense light the leaves are blood red. Higher temperatures, 24-28C/75-82F, will promote faster growth.
The accompanying photos illustrate (left to right) Ludwigia repens, L. repens "Rubin," L. repens X L. arcuata, and L. palustris X L. repens.
All of these varieties and hybrids are, like the subject species, marsh plants with creeping emersed shoots and erect submersed shoots. Yellow flowers will readily form in emersed cultivation, such as in a plaudarium or a garden pond, and sometimes with submersed cultivation they will form above water.
The Onagraceae is a family of some 650 species of flowering herbs, shrubs and trees, also known as the Willowherb or Evening Primrose family. The popular garden primroses are in this family, which is found from boreal to tropical regions on every continent (save Antarctica). The family was named after the botanic genus Onagra [now Oenothera] in 1836 by the English botanist John Lindley, and contains two subfamilies of which one is Ludwigioideae containing the single genus Ludwigia.
The genus Ludwigia was named by Carl Linnaeus, the Swedish botanist, physician and zoologist whose classification of all living organisms led directly to the modern system of binomial nomenclature. The name honours Christian Gottlieb Ludwig (1709-1773), a German physician and botanist. Botanists are not in agreement over many of the 75 nominal aquatic species in the genus, and changes may be expected from ongoing work in genetic studies of particularly the American species.
Kasselmann, Christel (2003), "Aquarium Plants," English edition published by Krieger Publishing Company.
Munz, P.A. (1965), "Onagraceae," North American Flora, series II, number 5.
Ideal position in aquarium
Provides a decorative background plant in any sized aquarium.
Moderate. Variants with red leaves will be more successful in brighter light.
Minimum Tank Suggestion
Ideal water parameters for Ludwigia
Soft to hard, slightly acidic to basic water, optimum temperature below 26C/79F except for the hybrids as detailed under "Physical Description." Higher temperatures can be tolerated but only short-term.