Plant of the Week

Simpson’s hedgehog cactus (Pediocactus simpsonii)

By Charlie McDonald

Map of the United States showing states. States are colored green where the Simpson's hedgehog cactus may be found.
Range map of the Simpson’s hedgehog cactus. States are colored green where the Simpson’s hedgehog cactus may be found.

Have you ever thought of looking for cacti on mountaintops? Well, that is where you can find Simpson’s hedgehog cactus. It grows at elevations of 4,600 feet up to 11,500 feet! Thus, many people call it mountain cactus. It grows in rocky soil on exposed ridges and is found in mountains throughout the interior West.

This is a beautiful little cactus. It is almost perfectly round, up to 6 inches in diameter, and is rather densely covered with smooth relatively stiff spines. It blooms from early May to June. Flower color can be white, pink, magenta, yellow, or yellow green. Its cold hardiness makes Simpson’s hedgehog cactus a favorite of cactus enthusiasts in northern climates.

Simpson’s hedgehog cactus, Pediocactus simpsonii.
Simpson’s hedgehog cactus variety robustior. Photo © 2004 Christopher L. Christie; from CalPhotos, used with permission.

Simpson’s hedgehog cactus is an exceedingly variable species. Many botanists recognize the varieties minor, robustior, and simpsonii. Simpson’s hedgehog cactus is in the small genus Pediocactus, which has eight species. Only Simpson’s hedgehog cactus is wide ranging and common; the other seven are rare endemics with five of them, Brady’s hedgehog cactus, Despain’s pincushion cactus, Knowlton’s cactus, Peebles Navajo cactus, and Siler’s pincushion cactus, included on the Federal endangered species list.

For More Information: PLANTS Profile - Pediocactus simpsonii, Simpson's hedgehog cactus

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Decumbent Trillium (Trillium decumbens).
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