Cleistocactus strausii, commonly known as the silver torch cactus, is a striking columnar cactus native to the mountainous regions of Bolivia and Argentina. This cactus is easily recognized by its tall, slender stems covered in a dense layer of silvery-white spines, which give it a soft, fuzzy appearance despite its sharp nature. The stems can grow up to 10 feet tall in ideal conditions and tend to cluster at the base, forming impressive groups over time. In summer, mature plants produce vivid crimson to magenta tubular flowers that emerge horizontally from the upper parts of the stems, often attracting hummingbirds and other pollinators.
Cleistocactus strausii thrives in bright, indirect light but can also tolerate full sun, particularly when acclimated gradually. In cooler climates, it is commonly grown as a container plant, easily overwintered indoors when temperatures begin to drop. This species prefers well-draining, gritty soil and benefits from occasional watering during the growing season, usually from spring to early autumn. It’s crucial to allow the soil to dry completely between waterings to avoid root rot, a common issue with overwatered cacti. During the winter months, watering should be minimal, as the plant enters a period of dormancy.
Temperature-wise, the silver torch cactus is relatively cold-hardy for a cactus, tolerating brief dips down to around 20°F (-6°C), provided it stays dry. However, it does best when protected from prolonged frost. Fertilizing can be done during the active growing season with a diluted cactus fertilizer to encourage healthy growth and flowering.
Propagation is typically achieved through seeds or cuttings taken from basal offsets. While growth can be slow initially, patience is rewarded with an architectural, sculptural plant that becomes increasingly impressive with age. With the right care, Cleistocactus strausii is not only a low-maintenance addition to any succulent collection but also a visually captivating one that brings a touch of desert elegance to gardens, patios, or indoor spaces.
