Scientific Name
Stenocereus pruinosus (Otto ex Pfeiff.) Buxb.
Common Name(s)
Gray Ghost Organ Pipe
Synonym(s)
Cereus pruinosus, Echinocactus pruinosus, Griseocactus pruinosus, Griseocereus pruinosus, Lemaireocereus pruinosus, Neogriseocereus pruinosus, Rathbunia pruinosa, Ritterocereus pruinosus
Scientific Classification
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Pachycereeae
Genus: Stenocereus
Etymology
The specific epithet "pruinosus" (pronounced "proo-in-NO-suh") means "frosty, frosted" and refers to the stems of this species, which are often covered with powdery bloom near the tips.
Origin
This species is native to south-central Mexico.
Description
Stenocereus pruinosus is a large shrubby or tree-like cactus with a distinct trunk from which the branching stems arise. It can grow up to 16 feet (4.9 m) tall and 10 feet (3 m) wide. The stems are gray-green, often with powdery bloom near the apex, and can reach a diameter of 4 inches (10 cm). They have 6 to 10 very high ribs lined with areoles. Spines are grey to brownish and can measure up to 1.2 inches (3 cm) long. Each areole bears 1 to 4 central and 5 to 8 radial spines.
The flowers are white, funnel-shaped, and appear on new growth at the stem tips in summer. The fruits are egg-shaped and can grow up to 3.2 inches (8 cm) long. They change color from yellow to orange-green and purple.

Hardiness
USDA hardiness zones 9b to 11b: from 25°F (-3.9°C) to 50°F (10°C).
How to Grow and Care
Like most cacti, Cereus is a fairly low-maintenance and hardy plant. Ensure they receive sufficient water without becoming waterlogged, especially during the summer, and fertilize them for optimal growth and results. If the roots have become black or overly soft, the cactus could be experiencing root rot. Cut away the affected parts and replant. Most gardeners interested in cacti should be able to cultivate these without much problem.
It may become necessary to repot your Cereus if it outgrows its container. If so, ensure the soil is dry and remove the pot. Knock away old soil, prune away any rotted or dead roots, then replace it in a new pot and backfill it with new soil. Ensure not to overwater cacti planted in new pots, as this can lead to root rot. It should be left dry for about a week and then watered lightly.
These cacti propagate quite easily from cuttings. Simply sever a branch and replant in moist, well-drained soil.
See more at How to Grow and Care for Cereus.
Links
- Back to genus Stenocereus
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus
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