Astrophytum myriostigma 'Multicostatum'

DESCRIPTION
The Bishop's Cap Cactus 🌿, scientifically known as Astrophytum myriostigma 'Multicostatum', is a striking member of the Cactaceae family native to the highlands of central Mexico. This particular cultivar features an impressive seven ribs instead of the typical five, creating a more complex geometric pattern that collectors find fascinating. Originating from limestone-rich regions where it grows slowly among rocky outcrops, this cactus has adapted to survive extended dry periods and intense sunlight. Care difficulty sits at intermediate level, requiring attention to watering schedules and light exposure. Here's something interesting: the white specks covering its surface aren't spines at all but tiny hair-like structures called trichomes that help reflect harsh sunlight and reduce water loss.
FOLIAGE AND GROWTH HABIT
This cactus grows in a solitary, dome-shaped form that maintains a neat, upright habit without spreading or trailing. The body displays seven well-defined vertical ribs that create clean, architectural lines running from base to crown. The surface colour ranges from greyish-green to silvery-green, heavily dotted with white trichomes that give it a frosted appearance. The texture feels smooth yet slightly fuzzy due to these hair-like structures, and the overall shape resembles a bishop's mitre or cap, which explains its common name.
FLOWER DETAILS
Mature specimens produce bright yellow, daisy-like flowers that emerge from the woolly crown during late spring and summer months. Each bloom measures roughly 5 centimetres across with delicate, satiny petals arranged in concentric layers around a dense centre of golden stamens. The flowers carry no noticeable fragrance but provide stunning contrast against the silvery body of the cactus. While individual blooms last only two to three days, healthy plants can produce multiple flowers throughout the growing season. To encourage flowering, ensure the plant experiences a cool, dry winter rest period with reduced watering and provide plenty of bright light year-round.
CARE INSTRUCTIONS
🌞 Light: Full sun to very bright indirect light. Requires 6-8 hours of direct sunlight daily, preferably morning sun with some afternoon protection during peak summer heat.
💧 Water: Water deeply but infrequently during spring and summer, allowing soil to dry completely between waterings. Reduce watering significantly in fall and stop almost entirely in winter. Bottom watering works well to avoid wetting the body.
🌡️ Humidity: Prefers low humidity between 20-40%. Thrives in typical dry indoor conditions.
🪴 Soil: Well-draining cactus mix with added pumice, perlite, or coarse sand. Needs excellent drainage to prevent root rot.
🏺 Potting: Shallow terracotta or unglazed clay pot slightly larger than the root ball. Repot every 3-4 years in early spring, handling carefully to avoid damaging roots.
🌱 Growth rate: Very slow growing. Expect 1-2 centimetres of growth per year. Can reach 15-20 centimetres in height and diameter at maturity after 10-15 years.
👩‍🌾 Fertilizing: Feed monthly during spring and summer with diluted cactus fertilizer at half strength. No fertilizing during fall and winter dormancy.
🐾 Pet friendly: Yes, this cactus is non-toxic to cats and dogs. However, the plant's shape and structure could cause physical irritation if chewed.
WHERE TO PUT IT
Place your Bishop's Cap Cactus on a south-facing windowsill, in a bright sunroom, or on a covered outdoor patio during warmer months where it receives ample direct sunlight. It works beautifully as a standalone specimen on a desk, side table, or grouped with other cacti and succulents in a bright display. Avoid placing it in bathrooms, kitchens, or any humid environment. Keep it away from drafty windows during winter and don't position it in low-light corners or rooms without adequate sun exposure.
RARITY ASSESSMENT
sought-after