TankBud

Needle hairgrass

Eleocharis acicularis

Also known as Needle spikerush

FreshwaterCarpetingRunners

Needle hairgrass (Eleocharis acicularis)
Aquarium Plants Factory · Used with permission

Care at a glance

Light
Medium light
CO2
CO₂ beneficial
Temperature
59–79°F
15–26°C
Max height
7.9 in
20 cm
Growth rate
Medium
Placement
Foreground
Type
Carpeting
pH
5.5–7.5
Hardness
1–14 dGH
Spread
5.9 in (15 cm)
Nutrient uptake
Root + water column
Growth region
Submersed or emersed
Difficulty
Easy
Family
Cyperaceae
Origin
Near-global (Europe, Asia, North America)

Overview

Needle hairgrass is an easy, grassy carpet plant for the foreground. It spreads aggressively by underground runners to form a lawn.

Did you know

Needle hairgrass thickens when you mow it short with scissors. Each cut blade triggers the plant to push out more runners and new shoots.

Caring for needle hairgrass

Plant small bunches of a few blades each, spaced out. Let the runners fill the gaps over several weeks.

Needle hairgrass wants medium light. Bright light keeps it growing low and dense, while in low light it stretches tall and thin and the carpet opens up. It grows without injected CO2, though CO2 roughly doubles the speed of filling in.

It feeds through its roots and leaves, so root tabs and a liquid fertilizer both help. It tolerates soft to fairly hard water at 59 to 79°F (15 to 26°C). Trim the lawn with scissors to an even height to keep it tidy.

Good to know

Needle hairgrass is a true sedge in the family Cyperaceae. Its relatives in the hobby include other Eleocharis spikerushes, such as E. parvula and E. montevidensis. Its thin green blades are not leaves but photosynthetic stems called culms, and the true leaves are reduced to sheaths at the base. Sometimes called the taller acicularis form, it grows taller than the smaller dwarf and 'Mini' selections.

In the wild

Needle hairgrass is an almost globally distributed spikerush. It is found across Europe, Asia and North America in ponds, ditches, lake margins and slow rivers. It grows both submersed and emersed and is hardy enough to overwinter outdoors in temperate climates.

Common questions

Does needle hairgrass need to be planted in the substrate?

Yes. Split it into small clumps and push each one into the substrate with tweezers, leaving gaps for it to fill.

Does needle hairgrass need CO2?

No, but it helps. Needle hairgrass can grow without injected CO2, and added CO2 makes it grow faster.

How much light does needle hairgrass need?

Needle hairgrass wants medium light. A light sold for planted tanks covers it.

Does needle hairgrass need root tabs?

They help. Needle hairgrass takes nutrients through both its roots and its leaves. Root tabs near its roots and a liquid fertilizer cover both.

How do you propagate needle hairgrass?

Needle hairgrass propagates by runners. New plants grow along its runners. Cut one free once it has roots and plant it.

How tall does needle hairgrass grow?

Needle hairgrass grows to about 7.9 in (20 cm) tall. It grows at a moderate pace.

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