Light
Full Sun
Thrives in full sun, requiring at least 6 hours of direct sunlight daily.
Reference image Cereus myriacanthus
Thousand-Spined Cereus
Overview
Cereus myriacanthus is a lesser-known columnar cactus belonging to the family Cactaceae. Characterized by its extraordinarily dense and fine spination, this species is a prized find for cactus enthusiasts and specialized collectors.
Taxonomy and Naming
Classified within the genus Cereus, its specific epithet myriacanthus is derived from the Greek words 'myrios' (countless or thousands) and 'akantha' (spine) 1. This name directly references the dense, brush-like spine clusters emerging from its closely spaced areoles.
Distribution and Habitat
This cactus is native to South America, particularly found in the dry valleys and rain-shadow regions of Peru along the Andean slopes 2. It thrives in rocky, gravelly soils that offer rapid drainage and receives minimal annual rainfall.
Appearance
The stem is erect, cylindrical, and light green to glaucous-green, featuring prominent longitudinal ribs. Each areole bears numerous fine, yellowish to grayish needles that almost completely obscure the epidermis. It produces nocturnal, funnel-shaped white or cream flowers that open for just one night.
Cultivation
In cultivation, it requires maximum sunlight and exceptional drainage. Water thoroughly during the active spring and summer growth phase, allowing the substrate to dry out completely. In winter, keep the plant dry and cool to encourage dormancy.
Common Cultivation Errors
Overwatering is the primary cause of failure, rapidly leading to root rot 1. Insufficient light exposure results in etiolation, causing the columnar stems to stretch weakly toward the light source, losing their characteristic dense spination.
References
Watering
10-30 Days
Water only when the substrate is fully dry. Minimize watering during the winter dormancy period.
Soil
Well-draining, sandy and gritty cactus soil mix
Requires extremely well-draining, mineral-heavy soil containing pumice, sand, and perlit.
Safety
Pet Friendly
Non-toxic, but the extremely dense and sharp spines can cause physical injury; handle with care.
Difficulty
Easy
Very easy to care for, provided it is not overwatered and is kept in a bright location.
Native Habitat
Peru, South America
Naturally distributed along the arid slopes of the Andes in Peru, growing in highly inorganic, rocky desert conditions.
Frequently Asked Questions
Can Cereus myriacanthus be grown indoors?
Yes, it can be successfully grown indoors on highly sunny windowsills.
How often should I water it?
Water when the soil is completely dry (approx. every 10 days in summer) and once a month in winter.
What kind of soil should I use?
Highly porous cactus soil enriched with pumice and coarse river sand is preferred.
What are its sunlight requirements?
It requires at least 6 hours of direct sunlight daily; partial shade will cause etiolation.
Is it toxic to pets?
It is non-toxic, but its dense, sharp spines can cause physical injury to pets.
Does it produce flowers?
Yes, mature plants produce large, nocturnal white or cream flowers during summer nights.
What is its growth rate?
It has a slow-to-moderate growth rate typical of columnar cacti.
What temperature does it need in winter?
Keeping it in a cool environment of 5-10°C (41-50°F) in winter is beneficial for dormancy.
What should I do if pricked by its spines?
The spines are fine and dense; remove them carefully with tweezers and wash the area with soapy water.
When should it be repotted?
Repot every 2-3 years in spring only if the root system has completely outgrown its current container.