Myriophyllum mattogrossense (green milfoil)

Overview

Myriophyllum mattogrossense, often sold simply as green milfoil, is a South American stem plant from Brazil's Mato Grosso region. Its finely divided leaves form fluffy, light green whorls, sometimes with a faint coppery tint at the tips. A healthy stand adds a soft, airy texture that contrasts nicely with broad-leaved plants.

Among milfoils, it is the one best suited to tropical aquariums: it needs less light than its relatives and tolerates a no-CO2 setup if fertilized well. It is a good intermediate plant for hobbyists past the basics. Some relatives, such as parrot feather (M. aquaticum) and Eurasian watermilfoil, are notorious invasive weeds, so never dump trimmings outdoors.

Care and tank setup

It suits tanks from about 15 gallons (55-60 liters) that are at least 16 inches (40 cm) tall. Plant it in the back or sides in groups with stems about an inch apart; crowded stems shade their own lower leaves.

• Light: medium to high. In low light the stems stretch and look sparse.
• CO2: optional, but it greatly improves density.
• Water: soft to moderately hard. In very hard, alkaline water it often shows deficiencies.
• Flow: moderate; strong current bends the stems.

It gets along with peaceful fish and shrimp. The fine leaves trap debris, so good filtration helps, and heavy substrate diggers are best avoided. A typical mistake is letting mulm or algae build up in the foliage, where it eventually causes rot.

Fertilizing and trimming

It is sensitive to iron and micronutrient shortages: if new tips come in yellowish or white, increase fertilization. Dose a complete liquid fertilizer weekly and add root tabs if your substrate is inert. Trim tops once they reach the surface and replant them. Every so often, gently shake the stand underwater or run the gravel vacuum nearby to clear trapped debris from the leaves.

Propagation

It is propagated from cuttings. Take 4 to 6 inch (10-15 cm) tops, remove the lowest whorls and push them about an inch into the substrate. They root in one to two weeks. Trimmed stems branch from the nodes, so the group becomes bushier. If the lower stems decline over time, replant only the tops. Toss extras in the trash or compost, never in natural waters.

Recommended equipment

What you need to keep the Myriophyllum mattogrossense (green milfoil) healthy, checked against Amazon stock.