Selaginella kraussiana, commonly known as Spikemoss, Trailing Spikemoss, or Clubmoss, is a unique plant often mistaken for a true fern or moss. This low-growing, spreading plant forms a dense, mat-like groundcover with delicate, fern-like foliage. Its vibrant green hue and creeping habit make it a popular choice for various indoor and outdoor settings.
Characteristics and Uses
Its fine, scale-like leaves are densely arranged along creeping stems, creating a soft, mossy texture. The stems branch frequently, allowing Selaginella kraussiana to spread horizontally, forming a verdant carpet. While the species presents a bright green color, cultivars like ‘Aurea’ display golden-yellow foliage, and ‘Variegata’ features white-tipped growth. It reaches a height of only a few inches but can spread extensively.
Selaginella kraussiana is versatile. It excels as a groundcover in shaded outdoor garden areas, particularly in humid climates, naturalizing beneath taller plants. Its high humidity requirements also make it an exceptional choice for terrariums and vivariums. Additionally, it is valued as an ornamental houseplant, providing a delicate, lush accent in pots or hanging baskets.
Growing Conditions and Care
Light
Selaginella kraussiana thrives in low to medium indirect light. Filtered sunlight, such as near an east-facing window or in a shaded part of a room, provides ideal illumination. Direct sunlight, especially intense afternoon sun, can quickly scorch its delicate foliage, leading to browning and crisping of the leaves.
Water and Humidity
Consistent moisture is important for Selaginella kraussiana, as it is highly sensitive to drying out. The soil should be kept consistently moist but never waterlogged, which can lead to root rot. Water thoroughly when the top inch of soil begins to feel slightly dry. High humidity levels are equally important; 70% or higher is beneficial. Increasing humidity can be achieved by placing the pot on a pebble tray, grouping it with other plants, or by growing it in a closed terrarium or cloche.
Soil and Nutrients
The ideal growing medium for Selaginella kraussiana is well-draining, rich in organic matter, and slightly acidic, with a pH range between 6.0 and 6.5. A mixture of peat moss, perlite, and a small amount of sand or fine bark provides the necessary drainage and moisture retention. As a light feeder, this plant does not require frequent fertilization. If desired, a balanced liquid fertilizer can be applied once every two to three months during the active growing season, diluted to half or quarter strength.
Temperature
Selaginella kraussiana prefers stable temperatures, thriving in a range between 60°F and 75°F (15°C to 24°C). It is not tolerant of extreme cold or significant temperature fluctuations. Exposure to temperatures below 50°F (10°C) can cause significant damage, leading to wilting and leaf loss. Similarly, prolonged exposure to temperatures above 80°F (27°C) combined with low humidity can stress the plant. Maintaining a consistent, warm environment helps ensure vigorous growth.
Propagation
Propagating Selaginella kraussiana is straightforward, primarily through division or stem cuttings. For division, carefully remove the plant from its container and gently separate the root ball into smaller sections, ensuring each new section has a portion of roots and foliage. These divisions can then be potted individually into fresh, moist soil. This method is best performed when repotting or when the plant has outgrown its container.
Stem cuttings offer another effective propagation method. Select healthy stems that are about 2 to 4 inches long, ideally with a few nodes. Remove any lower leaves that would be submerged in the rooting medium. These cuttings can be inserted into a moist, well-draining potting mix or rooted in a shallow dish of water. Maintaining high humidity around the cuttings, perhaps by covering them with a clear plastic dome, encourages successful rooting within a few weeks.
Common Issues
One of the most frequent problems encountered with Selaginella kraussiana is the browning or crisping of its delicate leaves. This often indicates insufficient humidity or inconsistent watering. If the foliage becomes dry and brittle, it is a clear sign that the plant is not receiving enough moisture from the air or soil. Increasing ambient humidity and ensuring the soil remains consistently moist, not just damp, can resolve this.
Conversely, yellowing leaves can signal overwatering or poor drainage. When the soil remains waterlogged, the roots can suffocate and rot, leading to a decline in plant health. Ensuring the plant is in a pot with adequate drainage holes and using a well-draining soil mix can prevent this. If yellowing occurs, allow the top layer of soil to dry slightly before the next watering. Pest issues are uncommon, but occasional spider mites can appear if the air is too dry; misting can help deter them.