Hair grass, also known as spike rush, is easy to grow within your pond or aquarium. It is named for its long, thin, threadlike leaves. It grows rapidly, sending out runners in all directions, at times proving to be somewhat invasive, especially in ponds and lakes. Depending on the species, hair grass will grow in a variety of water conditions and in a range of temperatures. Hair grass can be propagated from runners that have attached leaf growth called "slips."
Carefully dig and remove rhizome runners and slips from an existing patch of hair grass from within a pond or aquarium.
Remove the runners and slips from the water and rinse the remaining dirt from the root system.
Carefully separate the runners with attached slips by hand, ensuring that each runner has sufficient leaf growth to support it.
Continue this process until all runners required are dug, cleaned and separated.
Remove any dead or dying material from each plant. Do not allow the runners to dry out, as this will damage the roots.
Plant the new runners in your pond or aquarium at a depth equal to what they were growing at when harvested. Leave 2 to 4 inches between newly planted runners and slips to allow them to grow more freely. The planting will fill in, in time.
Trim the tops of the leaves two weeks after planting. This helps to control brush algae.
Vacuum the hair grass regularly to remove dying leaves or other debris that may collect on the "carpet" of grass.