Scientific Name
Echinocereus rigidissimus (Engelm.) F.Haage
Common Names
Arizona Rainbow Cactus, Rainbow Hedgehog Cactus, Sonorian Rainbow Cactus
Synonyms
Echinocereus rigidissimus subsp. rigidissimus, Echinocereus rigidissimus var. rigidissimus, Cereus pectinatus var. rigidissimus, Echinocereus pectinatus var. rigidissimus
Scientific Classification
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Pachycereeae
Genus: Echinocereus
Description
Echinocereus rigidissimus is a beautiful, usually solitary cactus, up to 12 inches (30 cm) tall and up to 4.4 inches (11 cm) in diameter, with pectinate radial spines curved slightly towards the stem. New spines are reddish to magenta and fades to a yellow or light pink when they mature. It blooms in flushes throughout the spring season, with multiple buds borne atop the plant from younger areoles. Flowers are bright pink with a white throat.

Photo via wikipedia.org
Hardiness
USDA hardiness zones 9a to 11b: from 20 °F (−6.7 °C) to 50 °F (+10 °C).
How to Grow and Care
If you can successfully grow other globular cactus, you can most likely grow Echinocereus well. One of the key factors in success with these is avoiding any hint of wet soil. Because their root systems are weak, they are especially prone to root rot, which will eventually kill your plant. Otherwise, they thrive on a program of strong, bright light, slight water and a steady diet of light fertilizer. These cacti are vulnerable to mealybugs and aphids.
Echinocereus are slow growing cacti that should only need repotting every other year or so. You can prolong the time to repotting by removing plantlets and potting them up in their own pots. When repotting a cactus, carefully remove it from its pot and knock away any clumped soil. These plants tend to be shallow-rooted with weak root systems, so take care not to damage their roots.
Learn more at How to Grow and Care for Echinocereus.
Origin
Echinocereus rigidissimus is native to Mexico (Chihuahua and Sonora) and United States (Arizona and New Mexico).
Subspecies, Varieties, Forms, Cultivars and Hybrids
Links
- Back to genus Echinocereus
- Succulentopedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus
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