Light
Full Sun
Requires full sun or direct bright light; shade causes weak, thin growth.
Reference image Cereus hexagonus
Lady of the Night Cactus
Overview
Cereus hexagonus is a massive, tree-like columnar cactus belonging to the Cactaceae family. Known for its impressive height and nocturnal blooms, it is a distinctive species adapted to wet tropical environments.
Taxonomy and Naming
Originally described by Carl Linnaeus, this species is a cornerstone of the genus Cereus. The specific epithet 'hexagonus' refers to the typical six-ribbed structure found on its mature branches 1. It is commonly known as the Lady of the Night Cactus or South American Blue Columnar Cactus.
Distribution and Habitat
Native to the Caribbean and northern South America, including Venezuela, Guyana, Suriname, French Guiana, and northern Brazil, this species thrives in wet tropical biomes 2. Unlike desert cacti, it prefers coastal hills, savannahs, and rocky outcrops within humid zones.
Appearance
This succulent tree can reach up to 15 meters in height. The stems are glaucous green, turning greyish-green with age, and feature 4 to 7 (usually 6) deep ribs. The large, nocturnal white flowers open for just one night, followed by edible, smooth, reddish-purple fruits.
Cultivation
In cultivation, Cereus hexagonus is valued for its rapid growth in full sun. It requires highly porous, mineral-rich soil and is highly sensitive to frost. While it enjoys regular watering during hot summer months, the substrate must dry out completely between waterings to prevent root rot.
Common Cultivation Mistakes
Overwatering and compacted soils are the primary causes of root rot. Insufficient sunlight leads to etiolation, where the plant grows thin, pale, and structurally weak.
References
Watering
10-25 Days
Allow soil to dry completely before watering. Reduce drastically in winter.
Soil
Well-draining, sandy and pumice-rich cactus soil mix
Highly porous, sandy, and mineral-heavy cactus substrate is essential.
Safety
Pet Friendly
Spines can cause physical injury. Handle with care. Non-toxic to pets.
Difficulty
Easy
Very easy to care for if given enough sunlight and drainage.
Native Habitat
Caribbean, Northern South America
Distributed across the Caribbean and northern South American regions like Venezuela and Brazil, thriving in coastal savannahs and wet tropical biomes.
Frequently Asked Questions
Can Cereus hexagonus be grown in a pot?
Yes, young specimens can be grown in pots. However, because it grows rapidly and reaches massive sizes, it will eventually require large, heavy containers for stability.
Is it toxic to pets?
No, *Cereus* cacti are non-toxic to pets. However, due to its sharp spines, it should be kept out of reach to prevent mechanical injuries.
How often should it be watered?
In summer, water thoroughly once the soil dries out completely (about every 10 days). In winter, reduce watering to once every 25-30 days.
What kind of soil does it prefer?
It prefers sandy, pumice-rich, and highly draining cactus soil mixes. Avoid clayey and heavy soils that retain moisture.
When does it bloom?
Mature plants usually bloom during the summer. The large, white, fragrant flowers open at night and close by the following morning.
How fast does it grow?
Under sunny and warm conditions, it grows quite fast compared to other cacti, potentially gaining 30 to 50 cm of height per year.
Is it frost tolerant?
No, it is sensitive to cold. It can tolerate temperatures down to 5°C. In frost-prone regions, it must be brought indoors during winter.
Why is my cactus turning soft?
Softening is usually a sign of root rot caused by overwatering. Stop watering immediately and, if necessary, take cuttings from healthy tops to re-root.
How is it propagated?
It can be easily propagated from stem cuttings (allowed to callus before planting) or grown from seeds.
Does it need direct sunlight?
Yes, it needs at least 6 hours of direct sunlight daily for healthy and sturdy growth. Insufficient light causes the plant to grow thin and weak.