Hygróphila corymbósa "Siamensis". (Blume) Lindau. Hygrophila corymbosa 'Siamensis' is a very hardy aquarium plant that is both readily available and easy to grow. This variety is commonly cultivated by nurseries, and can be purchased from numerous aquarium shops, online vendors, and through trade with fellow hobbyists. It is one of several H. corymbosa varieties found all over Southeast Asia. With the exception of very small aquariums and those with almost no illumination, there is no situation in which H. corymbosa 'Siamensis' cannot find a good home. Lighting and nutrient demands are moderate, as are those relating to nutrients. In addition, a wide variety of water hardness levels and temperatures are tolerated. It should be noted, however, that this plant will show symptoms of iron deficiency, such as green veins with yellowish surrounding tissue, if grown under high light but with inadequate iron levels. Likewise, problems with stunting can occur in fast growing specimens if macro nutrient levels dip too low. Fertilize as you would with most other plants and everything should be fine. To get the most out of H. corymbosa 'Siamensis', supply additional iron and light. In response, it will take on an attractive bronze hue. Otherwise, it will remain green. H. corymbosa 'Siamensis' is an excellent plant for novice keepers of emersed aquarium plants, as it is able to withstand a wide range of conditions and everything just short of outright abuse. A dosing routine similar to what would be used for submersed culture works well. Its attractive purple flowers are abundantly produced when things are going well. The only problem commonly encountered is an infestation of the leaves by something that looks like large raised salt grains, the cause of which the author is unable to explain. The condition does not seem to affect the plant much and has not been seen to spread to other species. H. corymbosa 'Siamensis' is an outstanding plant for mid to back ground plantings. Although it is a fast grower and requires some work, it is hardly laborious to maintain. It may be topped and replanted for an orderly stand or simply topped for a fuller one, since side shoots quickly appear after trimming (in addition to the many it produces on its own). A terraced grouping is very pleasing. Perhaps its best use is as a plant in an Asian-themed or biotope aquarium, where it exists harmoniously with Cryptocoryne species and cyprinid schooling fish like Trigonostigma espei or T. heteromorpha rasboras. Source: http://www.aquaticplantcentral.com/forumapc/plantfinder/details.php?id=226
