Scientific Name
Echinocactus platyacanthus Link & Otto
Common Names
Giant Barrel Cactus, Giant Viznaga, Large Barrel Cactus
Synonyms
Copiapoa macracanth, Echinocactus arachnoideus, Echinocactus aulacogonus, Echinocactus edulis, Echinocactus ghiesbreghtianus, Echinocactus grandis, Echinocactus helophorus, Echinocactus ingens, Echinocactus irroratus, Echinocactus karwinskii, Echinocactus macracanthus, Echinocactus minax, Echinocactus oligacanthus, Echinocactus platyceras, Echinocactus saltillensis, Echinocactus tuberculatus, Echinocactus viznaga, Echinofossulocactus helophorus, Echinofossulocactus karwinskianus, Echinofossulocactus macracanthus, Echinofossulocactus platyceras, Melocactus ingens, Melocactus platyacanthus, Melocactus tuberculatus
Scientific Classification
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Cacteae
Genus: Echinocactus
Description
Echinocactus platyacanthus is a slow-growing cactus with a grayish-blue, heavily ribbed, usually solitary stem with black straight, rigid spines. The stem grows up to 8.2 feet (2.5 m) tall and up to 5 feet (1.5 m) in diameter. The apex of the stem is flat and covered with a yellow felt-like substance. Flowers are diurnal, tubular, vivid yellow, up to 2.8 inches (7 cm) in diameter, and appear at the end of spring and summer. Fruits are yellowish, 1.2 inches (3 cm) long, and up to 1 inch (2.5 cm) in diameter. This cactus can live over 100 years.

Hardiness
USDA hardiness zones 9b to 11b: from 25 °F (−3.9 °C) to 50 °F (+10 °C).
How to Grow and Care
These cacti do best in a very sunny window, perhaps a southern exposure. Plants that do not get enough sunlight will grow more slowly and fail to thrive.
It is critical never to let these cacti be exposed to prolonged periods in water or even very high humidity. They will suffer from rot in the presence of humidity.
Echinocactus are vulnerable to pests, including aphids, mealybugs, scale, and whitefly. If possible, identify the infestation as early as possible and treat it with the leave toxic option.
It is best to repot at the beginning of the growing season or summer. To repot a cactus, make sure the soil is dry before repotting, then gently remove the pot. Knock away the old soil from the roots, making sure to remove any rotted or dead roots in the process.
Learn more at How to Grow and Care for Echinocactus.
Origin
Echinocactus platyacanthus is native to central Mexico in the Chihuahuan Desert.
Links
- Back to genus Echinocactus
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus