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

Category:

Cactus and Succulents

Height:

under 6 in. (15 cm)

Spacing:

9-12 in. (22-30 cm)

12-15 in. (30-38 cm)

Hardiness:

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

Danger:

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

Bloom Color:

Pale Pink

White/Near White

Cream/Tan

Bloom Time:

Mid Spring

Late Spring/Early Summer

Foliage:

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:

Non-patented

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

Regional

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

Tucson, Arizona

Gardeners' Notes:

1
positive
1
neutral
0
negatives
RatingContent
Neutral

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

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