If you're after a quick fix for an instant carpet - you've just found it!
The dwarf spikerush, Eleocharis, is native to Australia and New Zealand and inhabits wetlands with different water levels. This grass growth best in cooler water, so avoid discus tanks. This delicate beauty is ideal for stone layouts in the Iwagumi style, as it results in a fresh "summer meadow". Like all eleocharis cut well back, which makes the plant even denser and more compact.
Grown on a 20x15cm mesh you simply drop it into position, give it a wiggle so the bottom is hidden and away you go. Watch it grow.