Giant hairgrass

Eleocharis montevidensis

Also known as Sand spikerush, Tall hairgrass, Montevideo spikerush, Eleocharis sp. 'Montevidensis'

FreshwaterCarpetingRunnersdivision

Giant hairgrass (Eleocharis montevidensis) — Aquarium Plants Factory · Used with permission

Care at a glance

Light: Medium light
CO2: CO₂ beneficial
Temperature: 64–82°F; 18–28°C
Max height: 11.8 in; 30 cm

Growth rate: Medium
Placement: Midground
Type: Carpeting
pH: 6.0–7.5
Hardness: 2–15 dGH
Spread: 5.9 in (15 cm)
Nutrient uptake: Root feeder
Growth region: Submersed or emersed
Difficulty: Easy
Family: Cyperaceae
Origin: A spikerush from the Americas that grows in wet sand, marsh edges, and shallow water, sending up dense stands of grassy stems.

Overview

Push small bunches into the substrate and let the runners fill in over time under moderate light. It is a root feeder that does best in a nutrient rich substrate, and CO2 thickens the stand and keeps it shorter. Brighter light holds it low and dense, while dimmer light lets it grow tall and wild.

In the wild

Giant hairgrass is a taller, thicker bladed spikerush than the dwarf hairgrasses, forming a grassy stand of slender green stems. It spreads by runners into a connected clump that reads as either a tall midground tuft or a loose background screen. Its height depends a lot on light and can range from a few inches to well over a foot.

Good to know

Spikerushes are sedges, so the upright green blades are actually leafless stems, each tipped by a small flower spike. The plant knits itself together by sending out runners that root and sprout new stems.