Astrophytum Myriostigma Tricostatum

Astrophytum Myriostigma Tricostatum

Astrophytum myriostigma ‘Tricostatum’ is a rare and highly prized three-ribbed form of the popular Bishop’s Cap Cactus. Native to Mexico, this distinctive cultivar is admired for its perfectly symmetrical triangular shape, spineless body, and attractive silvery-white speckling. Its geometric form and slow growth make it a favorite among cactus collectors.

Key Features

• Growth Type: Solitary, spineless cactus
• Stem: Globular when young, becoming short-columnar with age
• Ribs: Typically three prominent ribs, creating a striking triangular profile
• Surface: Covered with fine white trichomes (flecks) that give the cactus a frosted appearance
• Spines: None
• Flowers: Large, silky yellow flowers with a pale center, blooming from spring through summer
• Size: Grows 15–30 cm (6–12 inches) tall and 10–20 cm (4–8 inches) wide

Distinctive Characteristics

• Rare three-ribbed (Tricostatum) growth form
• Elegant architectural symmetry
• Spineless body, making it easy to handle
• Attractive silvery coating that helps protect the plant from intense sunlight

Growing Conditions

Light:
Prefers bright light to full sun. Gradually acclimate plants to strong sunlight to prevent scorching.

Soil:
Requires a very well-draining cactus mix, such as:

• 50% cactus soil
• 25% pumice or perlite
• 25% coarse sand or grit

Watering:

• Water thoroughly during the growing season.
• Allow the soil to dry completely between waterings.
• Keep almost dry during winter dormancy.

Temperature:

• Ideal range: 18–30°C
• Protect from frost and prolonged temperatures below 5°C.

Flowering

Mature plants produce beautiful yellow, daisy-like flowers from the crown during late spring and summer. Flowering is encouraged by:

• Bright sunlight
• Cool, dry winter dormancy
• Proper watering during the active growing season

Care Tips

• Use a clay pot to improve drainage and airflow.
• Avoid overwatering, particularly during winter.
• Feed monthly with a diluted cactus fertilizer during active growth.
• Repot every 2–3 years as needed.

Propagation

• Seeds: The primary method of propagation.
• The Tricostatum form may not always come true from seed, making well-formed specimens especially valuable.

Uses

• Premium collector’s cactus
• Architectural container specimen
• Rock and succulent gardens
• Indoor displays with bright light
• Exhibition-quality cactus collections