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Plant Profiles / Blue candle cactus
Photos: Wikimedia Commons
Blue candle cactus
Myrtillocactus geometrizans · Bilberry cactus, whortleberry cactus
A branching, candelabra-like cactus with striking powder-blue stems. Fast and tough, it's a favourite for modern pots.
Full sunLight
Every 2–3 weeksWater
Very easyCare level
Care at a glance
Light
Full sun
ShadeFull sun
Full sun for the bluest colour.
Water
Every 2–3 weeks
DryWet
Water when dry.
Humidity
Low
LowHigh
Dry air.
Temperature
5–40°C (41–104°F)
CoolWarm
Protect from frost.
Growth
Moderate, branching
SlowFast
Grows 1–4 m; slower in pots.
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 central Mexico, blue candle produces small edible berries in the wild. Its blue colour is strongest in full sun. It's commonly used as a grafting rootstock.
Best spots
Sunny balconies, rooftops, modern pots and bright interiors.
Plant facts
| Botanical name | Myrtillocactus geometrizans |
| Family | Cactaceae |
| Origin | Central Mexico |
| Plant type | Branching columnar cactus |
| Mature size | 1–4 m |
| Growth rate | Moderate |
| Spines | Short, dark |
| Flowers | Small cream flowers |
| Toxicity | Non-toxic |
| Propagation | Cuttings or seed |
Seasonal care calendar
J
F
M
A
M
J
J
A
S
O
N
D
Active growth
Fertilise
Keep dry
Active growthFertiliseKeep dry
Based on Southern Hemisphere seasons.
Troubleshooting
| Greener stems | Less sun. |
| Soft spots | Overwatering. |
| White marks | Sunburn or scale. |
| Thin growth | Low light. |
| Frost damage | Protect in winter. |
Common questions
Why is it blue?
A waxy coating that protects from sun.
Does it branch?
Yes, with age.
Is it pet safe?
Yes.
Can it grow indoors?
Yes, in very bright light.
