Stomatium mustellinum, often called the “toothplant” or “night-blooming ice plant,” is a succulent native to South Africa. Its name, from the Greek “stomation” meaning “open mouth,” describes its distinctive leaves that resemble tiny jaws with small teeth. This unique appearance, combined with its fragrant, yellow, star-like flowers that unfurl in the late afternoon or evening, makes it a fascinating addition for any succulent enthusiast. Growing as a perennial, clump-forming plant, it thrives in cultivation.
Ideal Growing Conditions
Light Needs
Stomatium mustellinum thrives in bright, direct sunlight. For indoor cultivation, a south-facing window is suitable, ensuring the plant receives at least six hours of light daily. When transitioning plants to brighter conditions or introducing them to full outdoor sun, gradual acclimatization prevents scorching. Insufficient light can lead to etiolation, where the plant stretches and develops weak, pale growth.
Watering Techniques
Watering Stomatium mustellinum requires a careful approach, as overwatering is a common pitfall. Use the “soak and dry” method: water deeply until liquid drains from the pot’s bottom, then allow the soil to dry out completely before watering again. During active growth in spring and summer, watering frequency may increase, but during winter dormancy, water sparingly or withhold it entirely. The plant’s fleshy leaves store water, making it tolerant of infrequent watering.
Soil and Drainage
The right soil mix is important for Stomatium mustellinum, demanding well-draining and gritty conditions. A succulent or cactus potting mix should be amended with 50% to 70% mineral grit, such as pumice, perlite, or coarse sand. This ensures rapid drainage and aeration, preventing water from lingering around the roots and leading to rot. Planting in containers with drainage holes facilitates proper water runoff.
Temperature and Airflow
Stomatium mustellinum is adapted to fluctuating temperatures, tolerating low winter and high summer conditions. While it can withstand some cold, soft succulents do not tolerate hard frosts and should be brought indoors if temperatures drop below freezing. Ideal growing temperatures are warm during active growth, with cooler, but frost-free, conditions during dormancy. Good air circulation helps prevent fungal issues, particularly in humid settings.
Nutrient Requirements
Stomatium mustellinum has minimal nutrient needs. Fertilizing is not necessary, but for faster growth, a diluted, low-nitrogen succulent fertilizer can be applied during the active growing season in spring and summer. Avoid fertilizing during dormancy, as the plant will not absorb nutrients, harming it. Over-fertilization can lead to weak growth and susceptibility to issues.
Propagation and Repotting
Stomatium mustellinum can be propagated through seeds or by dividing clumps. For seed propagation, sow fine seeds mixed with sand in a gritty, well-draining soil mix, maintaining consistent moisture through misting. Germination can take several weeks to months, requiring warm temperatures between 70-80°F (21-27°C). Division involves carefully separating established offsets and planting them in small containers with well-draining soil, ensuring they are kept dry for a week or two before the first watering.
Repotting is needed when the plant becomes root-bound or every few years to refresh the soil. When repotting, handle the plant gently to minimize root disturbance and select a pot only slightly larger than the previous one, ensuring it has drainage holes. Use a fresh batch of the recommended well-draining, gritty succulent soil mix. Repot when the soil is dry and delay watering for a few days after repotting to allow any damaged roots to heal.
Troubleshooting and Common Problems
Overwatering is the most frequent issue with Stomatium mustellinum, often leading to root rot. Symptoms include mushy, discolored leaves and a soft, decaying base. To address this, reduce watering frequency, ensure adequate drainage, and consider repotting into fresh, dry soil if rot is severe. Conversely, underwatering can cause leaves to shrivel or growth to stunt, remedied by slightly increasing watering frequency during active growth.
If the plant is not flowering, causes include insufficient light, an incorrect dormancy period, or the plant not yet reaching maturity. Moving the plant to a brighter location, ensuring appropriate seasonal cycles, and allowing it to mature can encourage blooming. While resistant to many pests, Stomatium mustellinum can occasionally attract mealybugs or spider mites. Regular inspection and treating affected areas with organic solutions, such as rubbing alcohol or insecticidal soap, can manage these issues. Leggy growth, characterized by elongated stems and sparse leaves, indicates insufficient light and can be corrected by relocating the plant to a brighter spot.