Add a soft, delicate look to your water garden with fairy moss, which is also known as water fern or mosquito fern. Koi love to nibble on its soft, fuzzy foliage. Because it floats freely on the surface, shading the water as it spreads, fairy moss helps to reduce algae growth. Its colorful fall leaf display is a great bonus; the foliage darkens to purple-red at season’s end. Bring some clumps indoors to overwinter in an aquarium or pan of water to replenish the pond supply in the next season.
Though it bears the common name fairy moss, this plant isn’t a moss at all but rather an aquatic fern. It’s native to areas of South America.
Growing Fairy Moss
Fairy moss is all about texture. This floating fern is ideal for water gardens of any size. In warm-winter areas where it's hardy, it can grow into a thick cluster that blocks out light below. This reduces the growth of algae and provides habitat for fish. Fairy moss is said to grow so thick that it can even create a barrier where mosquitoes won't lay eggs, hence the name mosquito fern.
How to Care For Fairy Moss
Fairy moss grows fastest in full sun (at least 6 to 8 hours of direct light per day), but it tolerates sites that see only morning sun. The less sun it gets, the slower fairy moss grows, which means it is less efficient at blocking algae and slower to improve water quality.
This is an easy plant to grow—all you need to do is float it on the water's surface. Once established, it usually grows quickly in warm weather. Once fall arrives, its foliage takes on reddish-purple tones.
In areas where it is reliably hardy, you can leave it outdoors in your water gardens. In colder areas, it's best to treat it as an annual; bring some indoors to overwinter in a bright place floating in a large bowl of water or aquarium. Take it back outside in spring after all danger of frost has passed.