Tropica Eleocharis Montevidensis

Eleocharis montevidensis, known as Giant Hairgrass or Large Spikerush, is a larger species within the Eleocharis (hairgrass) genus, native to the Americas from North to South America. In the aquarium, it grows as clusters of upright, thin, bright-green cylindrical stems reaching 20–40 cm — much taller than Dwarf Hairgrass (E. parvula) — creating a natural, grass-like effect in the midground to background.

Giant Hairgrass is valued in aquascaping for the soft, flowing movement of its long, thin stems under current, creating a graceful, dynamic visual effect. Unlike the flat lawn of Dwarf Hairgrass, E. montevidensis produces taller clumps with a more meadow-like, riparian quality.

The plant spreads by runners, gradually creating naturalistic clumps that can fill an entire background section. It is moderately easy to care for and less demanding than fine-carpeting species. While CO2 and good light improve growth significantly, it can grow in moderate light without CO2.

Tropica produces E. montevidensis in their standard potted aquatic plant range.

Light: Low to medium-high light (10–50 PAR). Moderate light without CO2 produces slower but viable growth. CO2 and high light produce faster, more vivid growth.

CO2: Optional but beneficial. CO2 injection (15–20 mg/L) significantly improves growth rate and density.

Substrate: Grows in most substrates. Root tabs or nutrient-rich soil support faster spreading.

Placement: Midground to background. Tall stems create a swaying grass effect behind shorter foreground plants. Plant in clusters of 5–15 stems.

Propagation: Spreads by runners. Allow to naturalize or trim runners to control spread.

Maintenance: Low. Trim excessively long stems if needed. Remove yellowing stems.

Water Parameters: pH 5.5–8.0, temperature 18–28°C. Adaptable.