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Plant Profiles / Silver torch cactus
Photos: Wikimedia Commons
Silver torch cactus
Cleistocactus strausii · Woolly torch
A slender, columnar cactus covered in fine silvery-white spines, with tubular red flowers sticking out sideways.
Full sunLight
Every 2–3 weeksWater
Very easyCare level
Care at a glance
Light
Full sun
ShadeFull sun
Full sun.
Water
Every 2–3 weeks
DryWet
Water when dry.
Humidity
Low
LowHigh
Dry air.
Temperature
-5–38°C (23–100°F)
CoolWarm
Hardy to frost when dry.
Growth
Moderate, columnar
SlowFast
Grows 1–3 m.
Soil
Cactus mix
LeanRich
Free-draining.
Fertiliser
Twice a year
RarelyOften
Diluted cactus fertiliser.
Pet safety
Non-toxic
SafeToxic
Non-toxic.
About this plant
Native to the mountains of Bolivia and Argentina, silver torch handles cold better than many cacti. It forms clumps of upright columns over time.
Best spots
Sunny balconies, rooftops, modern pots and gravel gardens.
Plant facts
| Botanical name | Cleistocactus strausii |
| Family | Cactaceae |
| Origin | Bolivia & Argentina |
| Plant type | Columnar cactus |
| Mature size | 1–3 m |
| Growth rate | Moderate |
| Spines | Fine silvery-white |
| Flowers | Red tubes |
| Toxicity | Non-toxic |
| Propagation | Offsets or seed |
Seasonal care calendar
J
F
M
A
M
J
J
A
S
O
N
D
Flowering
Active growth
Keep dry
FloweringActive growthKeep dry
Based on Southern Hemisphere seasons.
Troubleshooting
| Soft base | Overwatering. |
| Thin tip | Low light. |
| Leaning | Uneven light. |
| Mealybugs | Treat with alcohol. |
| Toppling | Use a heavy pot. |
Common questions
Does it flower?
Yes, once around 45 cm tall.
Is it cold hardy?
Fairly, if kept dry.
Is it pet safe?
Yes.
Does it cluster?
Yes, with age.
