Myriophyllum tuberculatum

Myriophyllum tuberculatum populates slow-flowing and stagnant waters in the Asian tropics. In Europe, this milfoil is readily available in trade, in the US, however, it is not very widely spread yet. Most shops and online shops there erroneously carry another, less spectacular reddish-brown Myriophyllum native to Florida under that name.

The red watermilfoil was (and sometimes still is) sold for around 20 years under the erroneuous names M. mattogrossense and M. pinnatum. However, in 1994 it was identified as M. tuberculatum by botanist A. E. Orchard - after true, green M. mattogrossense had been imported from Ecuador by Christel Kasselmann in 1990.

M. tuberculatum is rather difficult in cultivation. It needs intensive light with at least 0.8 watts per litre, and CO2 injection is indispensable. Nitrates and phosphates should be maintained on a good level (5 to 15 and 1 to 2 mg/l, respectively). None of these main nutrients should ever fall to zero, otherwise the plant growth will be stunted. M. tuberculatum needs more iron and trace nutrients than most other stem plants. Without sufficient micronutrients the stems of this species remain very dark and small, and if there is an extreme deficit, the formative tissue of the shoot tip dies off. Under favourable conditions, the leaf whorls of M. tuberculatum can grow to a maximum diameter of around 10 cm and attain a rusty red colour.

Under good conditions this milfoil grows quickly to the water surface, where it grows lots of lateral shoots and develops a bushy habit. This species is best trimmed by removing the old stem and re-planting the strong upper part, as the rooted lower part only sprouts new shoots relatively slowly. For propagation, just cut off a lateral shoot and re-plant into the substrate.

As any other red stem plant, this species is highly recommendable for setting colourful accents. A healthy group of M. tuberculatum is a real eyecatcher, a stunning fireball that draws all eyes. The plant is a great accompaniment for green Myriophyllum and Limnophila species. Its finely-structured leaves and its moderate size also makes it suitable for smaller planted tanks.