Eleocharis montevidensis Care Guide
Eleocharis montevidensis, or giant hairgrass, is a tall spikerush with upright blades used for background hairgrass meadows.
Compiled by Aquairi from published sources · Published · Updated
Overview
Eleocharis montevidensis, known as giant hairgrass or sand spikerush, is a tall, slender grass-like plant of the sedge family (Cyperaceae). Its long upright blades make it well suited to tall background hairgrass meadows.
Taxonomy
- Family: Cyperaceae
- Genus: Eleocharis
- Scientific name: Eleocharis montevidensis
- Common name: giant hairgrass, sand spikerush
Habitat
Giant hairgrass is native to North and South America, where it thrives in shallow wetlands and along marshy shorelines. It tolerates tannin-rich water typical of blackwater environments and can grow both emersed and submersed.
Aquarium requirements
- Temperature: 18-28 °C (64-82 °F)
- pH: 6.0-7.8
- GH: 3-14 °dGH
- Lighting: medium
- CO2: not required
- Placement: background
- Maximum height: about 30 cm
The plant is undemanding, thriving under moderate light with or without CO2. In brighter light it tends to stay shorter and tighter, while moderate light encourages taller, more open growth. It is a root-feeding species that benefits from a nutrient-rich substrate or root tabs.
Care and growth
Growth rate is fast. It can be trimmed without harming the plant, allowing it to be kept contained. As it spreads it forms a dense thicket that provides shelter for small fish and fry while taking up nutrients.
Propagation
Eleocharis montevidensis propagates by runners in the substrate, gradually forming a dense stand. Runners and divisions can be replanted to spread the meadow across the background.
Propagating Eleocharis montevidensis (Montevideo Hairgrass) by Runners
Overview
Eleocharis montevidensis is a rhizomatous perennial herb that forms tufts or mats of erect, firm stems up to half a meter tall. Like other spikerushes in the genus, it has photosynthetic stems but no true green leaves, the leaves being reduced to sheaths around the base of the stems. In the aquarium it builds a tall, grassy background meadow that spreads steadily across the substrate.
In nature it grows in moist, sandy environments such as lake margins, riverbanks, wet meadows and springs across the Americas, so it is well adapted to a nutrient-rich, waterlogged rooting zone.
Propagation Method: Runners
This species spreads vegetatively through rhizomes, the underground stems that let it form expanding tufts and mats. As the rhizomes creep outward they push up new upright stems, so a single planting gradually thickens into a continuous turf. Propagation is simply a matter of letting that mat establish and then dividing it.
Step-by-Step
- Let the original planting grow until the rhizomes have knitted into a dense mat of upright stems.
- Gently lift a section of the mat, or reach in and tease the rhizomes apart underwater to limit clouding.
- Divide the mat into small plugs, each holding a few stems with attached rhizome and roots.
- Replant each plug into the nutrient-rich substrate, spacing them a few centimetres apart so they can fill in.
- Press the rhizomes lightly into the substrate so the new plugs stay anchored while they root.
Conditions for Healthy Growth
- Substrate: a nutrient-rich, sandy rooting zone suits this fibrous-rooted feeder.
- Temperature: 18-28 C.
- pH 6.0-7.8, GH 3-14.
- Lighting: medium light keeps the stems upright and dense.
- It is a fast grower and can also grow emersed.
Maintenance
Trim the meadow roughly every two weeks to keep the blades even and to encourage thicker, lower spreading. Periodically thinning the mat and replanting the divided plugs prevents the centre from becoming congested and shaded out.
Common Challenges
As a strong root feeder in a fibrous-rooted, rhizomatous plant, sparse or pale growth usually points to a poor or exhausted substrate rather than the water column. A dense, undivided mat can also shade and starve its own centre, so regular splitting keeps it vigorous.