Rotala wallichii is an elegant stem plant found in soft, acidic bodies of water in southeast Asia, where it is much more often found growing submerged and in deeper water than related species. It produces flower spikes adorned with bright, purple flowers. Although not the easiest of aquatic plants to grow, R. wallichii is one of the most popular, commonly available red stem plants in the hobby.
R. wallichii requires bright illumination, CO2 injection, and a balanced fertilization regime to thrive. Lighting should be at least 2 watts per gallon for best coloration and growth. Ample, steady amounts of CO2 from either a do-it-yourself yeast or a pressurized system is needed. Nitrate should be dosed for consistency, with smaller, more frequent doses being better. This plant grows best when nitrates are not allowed to reach zero but not kept over 20-25 ppm. R. wallichii appreciates relatively high phosphate levels (1-2 ppm) and heavy iron/micronutrient dosing. When conditions are good, this plant will reward the hobbyist with luxuriant, bright pink, orange, or deep red stems one inch or greater in diameter. Unfortunately, it is a frequent target of fish and invertebrates inclined to browse on aquatic vegetation, so care should be taken when choosing fauna.
This Rotala forms luxurious, fluffy, pink groupings which grow to the water's surface. This plant produces its most colorful, vibrant growth along the water's surface, where it also develops the greatest number of side shoots. When it gets too tall, R. wallichii can be pruned by cutting off the tops and leaving behind the rooted portions or uprooting the rooted portions and replanting the tops. Propagation can be performed by simply snipping off stems that are too tall and replanting them in the substrate.
R. wallichii is often used in both Nature Aquarium style and Dutch style layouts as a colorful, reddish accent located in the midground or background. For best effect, it should be planted three to five stems at a time with a pair of tweezers to form large, dense groupings.