The Cobweb Houseleek (Sempervivum arachnoideum) is a unique succulent with a distinctive appearance. Also known as Cobweb Hens and Chicks, this resilient, low-maintenance plant is a popular choice for outdoor spaces, thriving even in challenging conditions.
Understanding Cobweb Houseleek
The Cobweb Houseleek forms compact rosettes of fleshy leaves, typically green or reddish depending on variety and sun exposure. Its most striking feature is the fine, silvery-white hairs stretching between leaf tips, creating a delicate, web-like appearance. These protective “webs” shield the plant from intense sunlight and reduce water loss. Native to the rocky, mountainous regions of Europe, including the Alps, Apennines, and Carpathians, Sempervivum arachnoideum is exceptionally hardy, tolerating diverse environmental conditions.
Caring for Your Cobweb Houseleek
Cobweb Houseleeks thrive with environmental considerations that mimic their native alpine conditions. Providing the right balance of light, water, soil, and good air circulation supports their vigorous growth and distinctive appearance.
Light
This succulent requires ample sunlight to maintain its compact form and vibrant coloration. Full sun (at least six hours daily) is recommended. While it can tolerate some afternoon shade, especially in hot climates, insufficient light can lead to etiolation, causing the plant to stretch and become leggy. This results in a less dense and visually appealing plant.
Water
Cobweb Houseleeks are drought-tolerant, storing water in their fleshy leaves. The “soak and dry” method is ideal: water thoroughly, then allow the soil to dry completely before the next application. Overwatering is a common issue leading to root rot, so allow the soil to dry between waterings. During cooler, dormant months, reduce watering frequency significantly.
Soil
Well-draining soil is crucial for Cobweb Houseleeks. A gritty mix prevents moisture from lingering around the roots, which can cause rot. A commercial succulent or cactus mix is suitable, or create a homemade blend with perlite, pumice, or coarse sand for improved drainage. This mimics the lean, rocky soils of their natural mountainous environment.
Temperature and Airflow
Cobweb Houseleeks are remarkably cold-hardy, typically thriving in USDA Zones 5 to 8, enduring temperatures as low as -20°F to 20°F (-28.9°C to -6.7°C). They also tolerate heat, though they may enter brief dormancy during very hot summer months. Good air circulation is beneficial, especially in humid conditions, as it helps prevent fungal issues and promotes plant vigor.
Planting and Placement
Cobweb Houseleeks are versatile plants suitable for various outdoor settings due to their low-growing, mat-forming habit. They excel in rock gardens, colonizing hot, dry areas among stones. They are also excellent choices for xeriscaping, trough gardens, and containers, where their unique texture and form can be highlighted. As ground cover, they can form a dense, visually appealing carpet. While primarily outdoor plants, they can be grown indoors in locations receiving ample bright, indirect light, such as a sunny windowsill.
Propagation and Troubleshooting
Cobweb Houseleeks are known for their ease of propagation, primarily through the offsets they produce. These small rosettes, often called “chicks,” grow around the main plant, or “hen.” To propagate, separate these offsets when large enough, ensuring each has some roots attached, and replant in well-draining soil. This method allows for easy expansion of your collection.
While generally robust, issues can arise, often linked to care practices. Overwatering is a common problem, leading to soft, mushy leaves and root rot. Insufficient light can cause the plant to stretch and lose its compact rosette form (etiolation). Though less common, typical succulent pests like mealybugs can occasionally affect them, appearing as small, cottony masses.