The plant commonly known as Rainbow Moss, scientifically identified as Selaginella uncinata or Peacock Spikemoss, is not a true moss. It belongs to the ancient family of lycophytes, often called “fern allies” due to its delicate, fern-like foliage. This creeping, low-growing plant displays a vibrant, iridescent blue-green sheen. This shimmer makes Selaginella uncinata a favorite choice for specialized indoor environments like terrariums, which accommodate its need for consistent care.
Identifying Rainbow Moss and Optimal Light Conditions
Rainbow Moss is native to the floor of tropical forests in Southern China and Southeast Asia, thriving in perpetual shade. The plant’s distinctive blue iridescence is a result of structural interference, not pigment, where a thin layer of cells in the upper leaf cuticle refracts light. This adaptation helps the plant maximize light absorption in deep shade.
The plant requires low, indirect light to maintain its vibrant blue hue, needing filtered light indoors, such as from a north-facing window. Direct sunlight is detrimental, as the delicate foliage will quickly scorch and turn brown or red. Maintaining a warm, consistent temperature range, ideally between 60°F and 75°F, is also important.
Substrate, Humidity, and Watering Needs
Moisture management is crucial for successfully growing Selaginella uncinata. The ideal substrate is a loose, highly organic, and moisture-retentive mix that allows for adequate drainage. A combination of peat moss, coco coir, and perlite or vermiculite is recommended to create a humus-rich, slightly acidic environment. This composition ensures the plant’s shallow root system has constant access to moisture without becoming waterlogged, which leads to root rot.
The soil must be kept consistently moist and should never be allowed to dry out completely. During the active growing season, this may require watering every few days. When watering, use room-temperature water, as cold water can shock the plant and cause damage.
High ambient humidity is necessary for the Peacock Spikemoss to prevent its foliage from becoming dry and crispy. The plant demands a humidity level of 70% or higher, though it can tolerate a minimum of around 60%. Simple misting is often insufficient to maintain these high levels in a typical home environment. Practical solutions include keeping the plant in a closed or open terrarium, using a cloche, or placing the pot on a humidity tray filled with water and pebbles.
Propagation and Solving Common Issues
Propagation of Rainbow Moss is relatively straightforward and can be achieved through two primary methods. The first is division, which involves separating mature clumps into smaller sections, ensuring each new piece has some root structure. Since the plant’s stems naturally root where they touch moist soil, division is an easy process.
The second method uses stem cuttings, which are easily rooted in a moist substrate. A small section of a stem can be placed directly onto moist soil or sphagnum moss, where it will readily develop new roots. The best time to attempt propagation is during the active growing season, typically spring and summer.
The most frequent issue encountered is the browning or crisping of the foliage, which signals low humidity or insufficient watering. Indoor growers should monitor for common houseplant pests, such as spider mites, mealybugs, and fungus gnats. These pests can be managed by regularly wiping the leaves or addressing the overly moist conditions that attract fungus gnats.