Say it: KLY-stoh-cactus STROW-see-eye. Common names: silver torch, wooly torch, snow pole.
Where it grows
High valleys of Bolivia and northern Argentina, around 10,000 feet, where nights are cold and the sun is intense. Cephalocleistocactus ritteri, a close relative, also comes from Bolivia.
Size and growth
Slender, upright columns packed with short white spines, giving a frosted silver look. Strausii branches from the base into a cluster of poles 3 to 9 feet tall. Ritteri is shaggier, with longer hair-like spines. Fairly fast for columnar cacti: a foot or more a year once established.
Flowers
The genus name means “closed flower.” Tubular red flowers (yellow in ritteri) stick out from the sides of the stems but barely open, built for hummingbirds. Plants flower once the stems reach a few feet, often 5–8 years from seed.
Care
- Light: full sun for dense white spines.
- Water: regular in summer, dry in winter.
- Soil: gritty and fast-draining.
- Cold: strausii is hardy to around 15°F if dry; ritteri is a little more tender.
From seed
Easy. Germination in 7–21 days, and seedlings quickly grow upright and show their white spines.