Eleocharis acicularis

The Needle spikerush or Hair grass is a classic aquarium plant and one of the most beautiful turf-forming plant species with its almost hair-thin, medium-green culms. It is native to Europe as well as Asia, North, Central and South America and, as an amphibious plant, colonises open, occasionally flooded fine sandy soils, e.g. on and in lakes and ponds, in swamps and wet ditches. Very thin underground runners develop into a dense turf, which grows to a height of around 2 to 10 cm in the terrestrial form and sometimes up to 30 cm in the submerged form. In the aquarium, the Needle spikerush usually grows to a height of around 10 to 20 cm, in contrast to Eleocharis pusilla or E. sp. "Mini" at around 5 to 10 cm.

Eleocharis acicularis is not overly demanding, but should be planted in a bright and unshaded place. The addition of CO₂ is not a must, but, like a nutrient-rich substrate, it promotes the growth of the plant. Its delicate rhizomes and roots are best supported in a fine-grained substrate such as sand and aquasoil powder. The Needle spikerush tolerates a wide temperature range from near zero to (at least) 27 °C, with 20 - 25 °C being considered optimal. It is therefore suitable for cold water and moderately warm tropical aquariums. To achieve a larger lawn, divide the potted or in-vitro plant into a number of smaller clumps after removing the rockwool or tissue culture medium. These are placed in the substrate at a small distance from each other in the designated area. In a few weeks, the runners will grow together in the soil to form a closed lawn, and the denser the clumps are planted, the faster this will happen. Otherwise, the plant can be planted undivided and will then form more of a broad grass bush. The Hair grass can be kept relatively short by occasional pruning, but this Eleocharis species is recommended for a stand over 10 cm high. Propagation is easily achieved by dividing the plant.

The Needle spikerush is a versatile grass-like plant that is particularly recommended for cooler-temperature aquariums. While the dwarf hairgrasses (Eleocharis sp. "Mini" and E. pusilla) are particularly suitable for low lawns, Eleocharis acicularis is more suitable for a higher "meadow" or individual solitary tufts, also in combination with the other Eleocharis species. In emersed setups such as paludariums and Wabi-Kusa, a lawn of the Hair grass gives a natural impression; the emersed culms may then be adorned with small brown spikelets at the top.