Rotala macrandra
Botanical name: Rotala macrandra Koehne 1880

Rotala has about 46 species in tropical and temperate regions of the world.

Common Name: Giant Red Rotala

Family: Lythraceae
 
Region: India

Height: 25-55 cm (10-22”)
 
Width: 2-7 cm (1-2.5”)
 
Light requirements: high-very high
 
Temperature: 22-28 °C (71-82°F)
 
Hardness tolerance: very soft-medium
 
pH: 5-7
 
Growth: fast
 
Difficulty: Hard


Rotala macrandra is a beautiful aquarium plant. It is also quite demanding in its needs. It needs very good light to develop its beautiful red colour. It is most beautiful in groups, but do not plant individual shoots too close because this will prevent light reaching the lower leaves.

Rotala macrandra has red leaves that grow in pairs on each side of the slender stem. Rotala macrandra can have a dense growth under optimum conditions, with many ramulus (little branches) and thick clusters of leaves. This plant can be considered very soft and delicate. It never  becomes woody or tough. The leaves are thin, and as such are easily damaged.
 
It does require some special care to bring about this lush growth. Rotala macrandra requires fairly intense lighting conditions to bring out its best. It will grow under less intense light, but not as well, and if the water temperature is set higher than 82 degrees Fahrenheit, the plant is likely to brown off and dissolve. This plant will do best between 18-26°C (65-78°F).

Rotala macrandra can grow quite tall, reaching a height of almost 2 feet. If it is too thickly planted at the substrate, the lower portions of the stalk will suffer a leaf die-off from lack of light. This will cause the plant to look scraggly. Leave sufficient space (about 2 inches) between small groups of stems when planting, to avoid a plant that has all its leaves on the top part of the plant.

Propagation is most easily achieved by cuttings. When the plant is becoming too tall, or requires pruning, sections may be cut from the parent plant, at about 10-15 cm (4-6”) long. It’s best to cut the tops of the plant and replant those cuttings in the substrate for  the best appearance.

In order to maintain the bright red colour of Rotala macrandra, an iron-rich fertilizer is recommended. The colour of this plant is relative to how much light the plant receives. It becomes more red if provided with more light and the species needs a lot of light to thrive even though it might survive in less light.  Care is needed when treating your aquarium with medications since R. macrandra is sensitive to many of them (especially copper based).

I decided to get this plant only after having a tank that I knew I had high light in. This tank is a Fluval Osaka tank.  This tank has the rounded glass corners. This tank comes with 36" T5 high output double fluorescent fixtures with 2 bulbs. The tank is filtered with a Fluval 405.  I placed this in the center of the 70 gallon tank where it became the showpiece in the tank since it’s such a wonderful red colour.

This tank only gets monthly water changes since it’s lightly stocked.  The tank is not heated. It stays at room ambient temperature so it runs around 73°F (23°C) or so.

When I got this plant it was about 18cm (7”) high. It was only showing a light reddish colour.  When I first got it my tank was suffering through an algae bloom that took months to get rid of. I was forever cleaning the leaves off (carefully!) from the algae that would settle from the water column.  The rotala grew a lot taller. It soon reached the top of the tank.  The tank is 62 cm tall (24”). The top leaves got very red, but soon started blocking light to the lower leaves. Once I noticed the lower leaves starting to fall off the plant, I took some action. I trimmed the plant back down to about (31cm) 12” tall.  All the excess I trimmed off the plant I replant around the original stems to make my grouping larger.  These soon starting growing as well. The leaves on the plant are very bright red and I highly recommend this plant to someone who can grow it well.

 

© Copyright Lisa Boorman
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Suggested Reading:

Aquarium Plants : Their Identification, Cultivation and Ecology by Karel Rataj & Thomas J. Horeman

Aquarium Plants Manual by Ines Scheurmann

To check other plant references:

Plant and Pond Book List

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