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Mountain Cactus
Scientific Name: Pediocactus simpsonii Britton & Rose
Synonym: Pediocactus nigrispinus, Pediocactus nigrispinus ssp. puebloensis, Pediocactus simpsonii var. nigrispinus, Pediocactus simpsonii var. indranus, Pediocactus simpsonii ssp. indranus, Pediocactus nigrispinus var. beastonii, Pediocactus nigrispinus ssp. beastonii, Mammillaria simpsoni, Echinocactus simpsoni, Pediocactus simpsonii ssp. idahoensis
Family: Cactaceae
Recommended Temperature Zone:
USDA: 4-7

Minimum Avg. Temperature: 50F (10C)

Heat Tolerance: Comes from high elevation location, does not like excessive summer heat, particularly humid heat

Sun Exposure: Light shade

Origin: USA (Montana to northern Arizona), at 6000 to 10000 feet elevation (1800-3000 m)

Growth Habits: Solitary, light green stem, 1 to 6 inches tall (2.5-15 cm), 5 inches in diameter (12.5 cm), flattens in winter; spirally arranged tubercles, 0.25 to 0.6 inches long (6-15 mm); young areoles woolly; 5 to 11 pale yellow central spines on mature plants, 0.4 to 0.8 inch long (1-2 cm); 15 to 35 whitish radials, 0.25 to 0.5 inch long (6-12 mm)

Watering Needs: Regular water in late winter, early spring, and also in the fall, when it starts growing, very little water the rest of the time.


Cultural Practices:
Use a soil with little organic material.

Blooming Habits:
Bell-shaped flowers, pale pink or pale yellow, at the apex of the plant, 0.6 to 1 inch long and wide (15-25 mm). The fruits are spherical, green with an occasional reddish tinge, splitting open when ripe.

Fruiting Habits:

Check for Field Collection numbers at Ralph Martin's Site

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Desert-Tropicals is dedicated to provide gardening advice, gardening ideas, and information about flower of all kind for landscape and collections. We try to check carefully the identification of the plants on the illustrations as well as the other information from the page, but occasionally errors do occur. if you notice anything that needs to be changed please contact us. Thanks.

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