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PlantFiles: Gymnocalycium
Gymnocalycium riojense

Family: Cactaceae (kak-TAY-see-ee) (Info)
Genus: Gymnocalycium (jim-no-kal-LISS-ee-um) (Info)
Species: riojense (ree-oh-HEN-see) (Info)

Synonym:Gymnocalycium riojense subsp. riojense
Synonym:Gymnocalycium triacanthum

Cactus and Succulents

under 6 in. (15 cm)

9-12 in. (22-30 cm)
12-15 in. (30-38 cm)

USDA Zone 9b: to -3.8 C (25 F)
USDA Zone 10a: to -1.1 C (30 F)
USDA Zone 10b: to 1.7 C (35 F)
USDA Zone 11: above 4.5 C (40 F)

Sun Exposure:
Light Shade

Plant has spines or sharp edges; use extreme caution when handling

Bloom Color:
Pale Pink
White/Near White

Bloom Time:
Mid Spring
Late Spring/Early Summer

Unknown - Tell us

Other details:
Drought-tolerant; suitable for xeriscaping
Suitable for growing in containers

Soil pH requirements:
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)

Patent Information:

Propagation Methods:
From seed; direct sow after last frost

Seed Collecting:
Allow unblemished fruit to ripen; clean and dry seeds
Unblemished fruit must be significantly overripe before harvesting seed; clean and dry seeds

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By smashedcactus
Thumbnail #1 of Gymnocalycium riojense by smashedcactus

By smashedcactus
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By CactusJordi
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By palmbob
Thumbnail #5 of Gymnocalycium riojense by palmbob


1 positive
1 neutral
No negatives

Gardeners' Notes:

Neutral Xenomorf On Apr 17, 2005, Xenomorf from Valley of the Sun, AZ (Zone 9b) wrote:

The 'riojense' subspecies has 5 radial spines and whitish to pinkish brown flowers.
The 'kozelskyanum' subspecies has 3 radial spines and the flowers are deep pink with darker throats.
The 'paucispinum' subspecies has 3 radial spines and white/off white blooms.
The 'piltziorum' subspecies has 3-5 radial spines that are initially erect then radiate. The flowers are lilac-pink.
The 'platygonum' subspecies has pearl-white scented flowers and 3 claw-shaped spines.

Positive palmbob On Aug 23, 2004, palmbob from Acton, CA (Zone 8b) wrote:

dark skinned Argentinian cactus with almost useless spines- just remnants making cactus relatively easy to handle


This plant has been said to grow in the following regions:

Tucson, Arizona

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