How to Grow Cobweb Houseleek
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Cobweb Houseleek
Sempervivum arachnoideum
succulentCobweb Houseleek is a tiny succulent with distinctive white, spider web-like hairs covering its rosette leaves, creating a silvery appearance. It forms compact, low-growing mats of foliage and produces delicate pink or red star-shaped flowers in summer. This alpine succulent is extremely cold-hardy and drought-tolerant, making it ideal for rock gardens and containers.
When should you plant Cobweb Houseleek in your zone?
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Example Cobweb Houseleek timeline · Pittsburgh, PA (Zone 6b)
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Plant Cobweb Houseleek
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Cobweb Houseleek
Late summer into fallBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Cobweb Houseleek dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9; exceptionally cold-hardy in zones 3-4
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Get my Cobweb Houseleek timeline →Growth Stages
Seedling/Propagule
4-8 weeksTiny rosettes with fine cobweb hairs beginning to form; leaves are pale green and tender
Keep in bright, indirect light; mist very lightly only if soil dries out completely. Do not overwater. Provide excellent drainage with pure grit or sand mix.
Juvenile Rosette
3-6 monthsSmall rosettes (0.5-1 inch diameter) with increasingly visible white webbing covering leaf tips and edges; silvery appearance develops
Gradually increase sunlight exposure. Water only when soil is completely dry. Keep in cool conditions if possible.
Mature Rosette
6-12 monthsFull-sized rosettes (1-2 inches diameter) with dense, prominent cobweb-like hairs creating striking silvery appearance; leaves may turn reddish under stress or full sun
Maintain sparse watering schedule. Full sun enhances web pattern and color. Remove any dead outer leaves. Watch for rot in wet conditions.
Flowering
4-6 weeksSingle flowering stem (inflorescence) emerges from the rosette center, reaching 2-4 inches tall with delicate pink, red, or pale flowers in loose clusters
Do not water the flowering rosette excessively. The parent rosette will die after flowering (monocarpic), but offsets surrounding it will continue growing.
Post-Flower Offset Production
Ongoing; new rosettes mature in 1-2 yearsParent rosette withers after flowering; numerous small offshoots or 'chicks' emerge around the dead center, creating expanding colonies
Remove dead flowering rosette debris. Allow offsets to establish undisturbed. Continue minimal watering. These chicks will become new mature rosettes.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with insecticidal soap or horticultural oil; ensure excellent air circulation; avoid overwatering which creates humid conditions
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Prevent with well-draining soil and minimal watering; remove affected plants; do not reuse infected soil; improve air circulation
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Rinse with strong water spray; apply insecticidal soap if infestation is severe; encourage beneficial insects
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Spray with miticide or neem oil; increase air circulation; mist lightly if spider mites appear in very dry conditions
Uses
Ornamental Container & Alpine Gardens
HouseholdCobweb Houseleek's distinctive silvery webbed rosettes make it a prized ornamental for rock gardens, alpine troughs, succulent containers, and fairy gardens. Its compact size and architectural form provide year-round visual interest with minimal maintenance. [source]
Pollinator Attraction
WildlifeThe delicate pink and red summer flowers attract bees, butterflies, and other pollinators, supporting local ecosystems while requiring virtually no deadheading or maintenance. [source]
Traditional Herbal Use
MedicinalHouseleeks have been used in traditional European herbalism as a folk remedy for minor burns, skin irritations, and warts, though scientific evidence is limited. The leaves contain mucilaginous compounds. [source]
Terrarium & Living Jewelry
CraftThe tiny rosettes are perfect for miniature terrariums, living wreaths, succulent bowls, and even jewelry-sized displays due to their compact growth and extreme durability. [source]
Green Roof & Drought-Tolerant Landscaping
HouseholdCobweb Houseleek is ideal for extensive green roofs, xeriscaping, and water-wise landscapes in cold climates due to its extreme drought and cold tolerance and minimal care requirements. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Cobweb Houseleek is not typically harvested for consumption or commercial use. For propagation: detach healthy offsets (chicks) after they develop tiny roots, allow to callus for 1-2 days, then plant in dry cactus mix. Harvest leaf cuttings by gently removing individual leaves, letting them callus, then pressing into moist gritty soil. Propagation is most successful in spring and early summer.
Fun Facts
- 🌱 The distinctive cobweb-like hairs (called trichomes) serve as an adaptation to the plant's alpine habitat, helping reflect intense sunlight and reduce water loss in rocky mountain environments.
- 🌱 Sempervivum means 'forever living' in Latin, referencing the plant's extreme longevity and ability to survive harsh conditions where few other plants thrive.
- 🌱 Cobweb Houseleek is monocarpic, meaning each rosette flowers only once in its lifetime (typically at 2-3 years), then dies, but produces numerous offspring around the parent before doing so, ensuring colony continuity.
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