Rotala macrandra is one of the most distinguishable red aquatic plants in the hobby known for its pulsating red leaves. This plant also is one of the most difficult and demanding plants to keep in the aquarium. Although difficult, it is an aquarium plant that is worthy of the challenge of cultivating.
Native to Southeast Asia and parts of India, it grows naturally on marshlands and alongside other riparian vegetation.
Rotala macrandra is also cultivated in other variants such as Rotala macranda var. Green (bright green leafs with slightly pink undersides) and Rotala macranda var. Variegated (a combination of the original variety and Rotala macranda var. Green). In addition to the distinction in leaf color, each variety is available to hobbyists in Narrow Leaf assortments.
Rotala macrandra is commonly known as Red macrandra and Giant Red Rotala.
Rotala macrandra requires generous amounts of light, carbon dioxide, cool water (less than 75 degrees Fahrenheit, or 24 degree Celsius), and a healthy substrate bed in order to be successful. Nitrogen limitation is also required to encourage the rich red hues from the leaves.
Preferred water hardness tends to be in the softer ranges, however, it has been known to grow in a KH of 8.
Rotala macrandra leaves will grow in opposite pairs along the length of stem. The plant can reach a height of 20 inches (50 cm) and the width of the plant can span approximately 1-2 inches (2-5 cm).
Rotala macrandra may require extensive time to adjust to new water parameters. When initially planted, the growth tip will often stop growing and the plant will remain stunted. Leaves will often curl and turn white which is a sign of poor nutrient uptake (particarlly micronutrients – calcium).
If the plant shows signs of sustainability in the aquarium, remember it does not respond well to trimming initially. Rotala macrandra should be allowed to grow to as large as it can without shading itself and other plants. Trim the healthy tops and replant. Bottoms may be left in to develop side shoots.
Over time, as Rotala macrandra shows signs of vitality in the aquarium this plant can be trimmed without many reservations. Propagation of stems should be at least 5 inches (13 cm) long before trimming from the source plant.
Rotala macrandra is a perfect plant in the midground areas where it can be exposed to aquarium light. It makes a great complementing plant in Dutch style aquascapes, and should be planted in 3-5 stems that are spread evenly apart (to avoid shading).
In general, the upmost portions of the stem and its leaves will develop a deeper red hue than the latter sections. Replanting these vibrant tops frequently at intervals will keep the group at its striking best.
Photo Credit: Alex Korakis