Pot Size: 3.5"
Accepted Scientific Name:
Sempervivum calcareum ‘Rubin’
Origin and Habitat:
Sempervivum calcareum is native to the mountainous regions of southern Europe, particularly the Alps, where it grows on rocky limestone slopes and crevices. These environments are characterized by intense sunlight, cold winters, and excellent drainage with minimal organic matter. The cultivar ‘Rubin’ has been selected for its rich red coloration and strong rosette form. Like the species, it is highly adapted to survive harsh, exposed conditions, including drought, wind, and freezing temperatures, making it ideal for rock gardens and alpine plantings.
Description:
Sempervivum calcareum ‘Rubin’ forms tight, symmetrical rosettes measuring 3–5 inches in diameter, gradually spreading to 6–12 inches wide through offsets. The fleshy, pointed leaves are blue-green at the base with intense ruby-red tips that deepen in color under full sun and cooler temperatures. The rosettes create dense clusters over time, forming an attractive mat. In summer, mature rosettes may send up a short flower stalk bearing star-shaped pink flowers, after which the individual rosette dies, replaced by surrounding offsets.
Cultivation:
Zone: Suitable for USDA zones 4 to 9.
Temperature: Tolerates temperatures from -30°C to 30°C.
Growth Rate: Moderate, spreading steadily through offsets.
Soil: Requires sharply draining soil; amend with pumice to improve aeration and prevent excess moisture.
Watering: Water sparingly, allowing soil to dry completely between waterings. Extremely drought-tolerant once established.
Fertilizing: Apply a diluted, balanced fertilizer every 2–3 weeks during the growing season, though minimal feeding is needed.
Light: Thrives in full sun; strong light enhances red coloration and compact growth.
Pests and Diseases: Generally pest-free; may be susceptible to rot in poorly drained or overly wet conditions.
Propagation:
Easily propagated by separating offsets (chicks) from the mother plant. Allow offsets to establish in well-draining, pumice-rich soil with minimal watering.
