Cobweb Houseleek
Sempervivum arachnoideum
Arachnid
About this plant
Sempervivum arachnoideum, commonly called Cobweb Houseleek, is a small succulent known for its rosettes covered with fine white hairs that look like spider webs. It forms dense clusters and produces star-shaped pink flowers in summer. This plant is popular for rock gardens, containers, and green roofs due to its drought tolerance and unique appearance.
Taxonomy
- Genus
- Sempervivum
- Family
- Crassulaceae
- Higher classification
- Order Saxifragales
- Plant type
- Succulent
- Lifespan
- Perennial
Origin & Distribution
- Native region
- Europe (Alps, Carpathians)
- Distribution
- Native to mountainous regions of Europe, especially the Alps and Carpathians; widely cultivated worldwide in temperate regions.
Care
- Light preference
- Full sun
- Suitable locations
- Outdoor, Balcony, Indoor, Greenhouse
- Preferred window facing
- South-facing, Southwest-facing, West-facing
- Watering frequency
- Rare
- Watering interval
- 14–21 days
- Humidity
- Low
- Minimum
- -30 °C
- Maximum
- 35 °C
- Optimal
- 15-25 °C
- USDA hardiness zones
- 3-8
- Soil pH
- 6.0-7.5 (neutral to slightly acidic)
- Soil type
- well-draining sandy or rocky soil, cactus or succulent mix
Watering. Water only when the soil is completely dry. Avoid watering the rosettes directly to prevent rot. In winter, water very sparingly or not at all.
Fertilizing. Fertilize sparingly once a year in spring with a balanced, diluted succulent fertilizer. Avoid over-fertilizing as it can weaken the plant.
Sempervivum arachnoideum is a hardy succulent that thrives with minimal care. It prefers sunny spots and well-draining soil. Overwatering can cause root rot, so water sparingly. It requires little maintenance and is suitable for beginners.
Propagation
- Propagation methods
- Division, Offsets, Seeds
- Care difficulty
- Easy
Ornamental features
- Flowering
- Yes
- Flowering period
- summer
Rosettes with cobweb-like hairs, pink star-shaped flowers, dense clumping form.
Toxicity & Safety
- Toxic to humans
- Non-toxic
- Toxic to pets
- Non-toxic
- Weed potential
- Not considered a weed
Non-toxic to humans and pets; safe to keep around children and animals.
Allergy information
- Allergy risk
- Low
- Allergy triggers
- Sap or latex, Skin contact
- Pollen level
- Low
Sempervivum arachnoideum is generally safe and unlikely to cause allergies. However, people sensitive to plant sap or pollen should handle it gently to avoid mild skin irritation. It produces little airborne pollen, so allergy risk is low.
Common problems
Overwatering can lead to root rot and fungal diseases. Poor drainage or too much shade may cause the plant to become weak or rot. Pests are rare but watch for aphids or mealybugs.
Uses
Used as an ornamental plant in rock gardens, containers, and green roofs. Its drought tolerance makes it ideal for xeriscaping.
Notes
Remove dead leaves to keep the plant healthy and attractive. It can be propagated easily by separating offsets. Avoid water sitting on leaves to prevent rot.