Rotala wallichii

Overview

Rotala wallichii, sometimes called whorly rotala, is a stem plant from South and Southeast Asia with ultra-fine, almost needle-like leaves packed into dense whorls. Grown well, the tips turn pink, red or purple, and a group looks like a soft feather duster swaying in the current.

It is one of the prettiest rotalas and also one of the fussiest. It is not a plant for a tank without CO2; in those conditions it falls apart within weeks. It is meant for hobbyists running high-tech planted tanks or aquascapes who want a fine-textured splash of color in the background or along the sides.

Care and tank setup

It can be grown in tanks from about 12 to 15 gallons (45-60 liters) with strong lighting, but conditions matter far more than tank size. Plant it in groups with stems about half an inch apart, in the back or sides where it gets direct light.

• Light: high. Without it, the plant drops its lower leaves and loses color.
• CO2: essential, stable and at adequate levels.
• Water: soft and slightly acidic. In hard water growth is stunted and tips become deformed.
• Substrate: a nutrient-rich aquasoil, which also helps soften the water.

It works with small fish and shrimp; diggers and plant eaters wreck its fragile stems quickly. Typical mistakes: buying it for a low-tech tank, planting it in the shade of taller plants and letting hair algae take hold, since it tangles in the fine leaves and is very hard to remove.

Fertilizing and trimming

It needs complete, regular fertilization: macronutrients (nitrogen, phosphorus, potassium) plus micronutrients with plenty of iron, which boosts the red tones. Whitish or twisted tips usually point to an iron or micronutrient shortage, or water that is too hard. Trim often to keep the group dense: cut the tops and replant them. If the bottoms go bare, replanting the whole stand from healthy tops works better than repeatedly cutting old stems.

Propagation

It is propagated from cuttings. Take 3 to 4 inch (8-10 cm) tops, carefully strip the lower leaves because the stems are thin, and plant them with tweezers in twos or threes. They root quickly when conditions are right. Trimmed bases send out side shoots. New stems may start out green; color develops once light, CO2 and iron are all sufficient.

Recommended equipment

What you need to keep the Rotala wallichii healthy, checked against Amazon stock.