Pack Size: 20, 100, 300
Year: 2026
Accepted Scientific Name: Gymnocalycium bodenbenderianum (Hosseus ex A.Berger) A.W.Hill
Synonym: Gymnocalycium riojense subsp. piltziorum Schütz ex H.Till & W.Till
Origin and Habitat:
Gymnocalycium riojense subsp. piltziorum is a distinctive cactus native to northwestern Argentina, particularly the Sierra de Velasco mountains in La Rioja Province. It inhabits dry, rocky slopes and mountainous terrain at elevations around 1,200 metres, growing in thin, mineral-rich soils over volcanic rock. These environments experience warm summers, cool winters, and seasonal rainfall followed by extended dry periods. Plants frequently grow among sparse shrubs and grasses, where surrounding vegetation provides partial protection from intense sunlight. The species is adapted to well-drained soils and limited moisture, developing a compact, flattened growth habit suited to its harsh natural environment.
Description:
Gymnocalycium riojense subsp. piltziorum is a slow-growing, solitary cactus characterized by its flattened, globular shape and distinctive grey-green to olive-brown epidermis, often developing bronze or purplish tones under strong sunlight. Mature plants typically reach approximately 2–4" in diameter and 1–2" tall, occasionally becoming larger with age. The body features broad, well-defined ribs divided into prominent, angular tubercles with noticeable chin-like projections. Each areole produces several stout, straight to slightly curved spines, ranging from pale grey to dark brown, creating an attractive contrast against the darker body. Mature specimens produce funnel-shaped flowers approximately 2–2.5" across, displaying delicate lilac-pink to purplish-pink petals. Flowers emerge near the crown during spring and summer, followed by small, elongated fruits containing numerous seeds. Its compact growth habit, distinctive rib structure, and attractive flowers make it a desirable addition to specialist cactus collections.
Cultivation:
Zone: 9–11; protect from prolonged frost and excessive winter moisture.
Temperature: Optimal growth at 18–28 °C. Maintain winter temperatures around 5–10 °C when kept dry.
Growth Rate: Slow, gradually developing a flattened, globular body with increasingly prominent ribs and spines.
Soil: A highly mineral, fast-draining cactus mixture containing pumice, fine gravel, and a small proportion of organic matter. A slightly acidic to neutral growing medium is suitable.
Watering: Water thoroughly during active growth, allowing the growing medium to dry between waterings. Reduce watering significantly during autumn and keep mostly dry during winter dormancy.
Fertilizing: Apply a diluted, low-nitrogen cactus fertilizer every 2–3 weeks during active growth. Discontinue feeding during winter.
Light: Bright light with several hours of gentle morning sunlight. Provide protection from intense afternoon sunlight, particularly during hot summer weather. Adequate light encourages compact growth and stronger body pigmentation.
Pests and Diseases: Susceptible to mealybugs, root mealybugs, spider mites, and root rot caused by excessive moisture or poorly draining growing media.
Germination Info:
Temperature: 27 °C.
Surface Sown: Yes. Sow seeds on the surface of a fine, sterilized cactus growing medium and press lightly into place without burying deeply.
Germination Time: Approximately 7–28 days under favourable conditions, although some seeds may require longer.
Moisture: Maintain consistent surface moisture and high humidity during germination, avoiding waterlogged conditions.
Light: Bright, indirect light. Avoid direct sunlight on covered seed trays.
After Germination: Gradually increase ventilation as seedlings establish. Maintain moderate moisture until young plants develop stronger root systems and begin producing characteristic ribs and spines.
