Plate No. 14

Silver Torch

Cleistocactus strausii

"A column wrapped in silver thread"

Native to

High Andes of Bolivia and Argentina, above 3,000 m

Botanical illustration of Silver Torch
Cleistocactus strausii — drawn from life
History

A brief account

Described in 1922 by the German cactus specialist Friedrich Vaupel and named for the botanist Strauss. Its dense coat of fine white spines reflects the fierce Andean sun. Mature plants produce striking horizontal red flowers that never fully open.

How to care for

Silver Torch (Cleistocactus strausii) grows best when its natural cycle of strong light, freely draining soil and measured watering is respected. Give it full direct sun. Water it according to its seasonal needs: moderate in summer; entirely dry in winter. Plant it in mineral cactus mix with extra grit. A container with an unobstructed drainage hole is essential, because moisture lingering around cactus roots can quickly lead to rot. Keep its temperature needs in mind: -5 to 30°c. among the more cold-hardy columnars. During active growth, check the compost before watering rather than following a rigid calendar, since heat, light and pot size all change how quickly it dries. Reduce watering during cool or dormant periods, keep the plant well ventilated, and wait until the growing medium is dry before watering again.

How to propagate

From seed; offsets are infrequent. Separate established offsets during the warmer growing season, using clean tools and preserving any roots already attached. Allow damaged surfaces to callus before potting into a dry, mineral-rich mix, then water cautiously while the new root system establishes. Young cacti are especially vulnerable to excess moisture. Use a small pot with excellent drainage, provide bright filtered light while roots establish, and move the new plant gradually into the light, temperature and watering conditions preferred by a mature Silver Torch.
Cultivation

Quick tips for care & planting

Light
Full direct sun.
Water
Moderate in summer; entirely dry in winter.
Soil
Mineral cactus mix with extra grit.
Temperature
-5 to 30°C. Among the more cold-hardy columnars.
Propagation
From seed; offsets are infrequent.