Bishop's Cap Cactus

Overview

The bishop's cap is a spineless, sculptural little cactus shaped like a plump star or a bishop's mitre, its few broad ribs dusted all over with tiny white woolly flecks. Slow, tidy and utterly distinctive, it is a prized, hand-friendly collector's cactus that flowers generously for its size.

Origin & Natural Habitat

Astrophytum myriostigma is native to the high deserts and limestone hills of northern and central Mexico, growing on sun-baked, mineral-rich ground. It has been a collector's favourite for well over a century.

Appearance

A rounded, spineless body divided into (usually) four or five prominent ribs, giving a clean star shape from above and a mitre-like profile from the side. The whole surface is speckled with small white woolly flecks (trichomes) over a grey-green skin, and glossy yellow flowers with an orange throat open at the crown in the growing season.

Why People Love It - Qualities & Benefits

Collectors love the geometric star form, the spineless (child- and hand-friendly) surface, and the fine white speckling. It is a small, slow, living sculpture that blooms reliably and asks very little.

Care

Light

Bright light with several hours of direct sun keeps the ribbed star form tight and encourages flowering - a sunny, south-facing windowsill is ideal. Too little light and the neat shape softens and stretches.

Watering

Soak thoroughly, then let the soil dry out completely before watering again, and keep it nearly dry through winter. Like all astrophytums it is prone to rot, so lean dry and never let water sit on the crown.

Soil & Potting

A very gritty, sharply draining cactus mix with extra pumice or grit, in a pot with drainage. This limestone-loving genus especially resents wet roots, so mineral, fast-draining soil is essential.

Humidity & Temperature

Warm, dry air is essential; it dislikes humidity. Ordinary dry room air suits it well. Keep it warm and give a cool, dry, frost-free winter rest to set the spring flowers.

Feeding

A dilute cactus feed once or twice in the growing season is plenty; this slow plant needs very little feeding.

Repotting

Repot rarely, only when pot-bound, in spring. Being spineless it is easy to handle, but treat the sensitive roots gently and wait a week before watering after repotting.

Propagation

Bishop's cap is grown from seed, which germinates readily but grows slowly, as it rarely offsets. Seed from a reputable source is the main route - a rewarding project for the patient collector.

Common Problems & Pests

Root and base rot from overwatering or cold, wet soil is the main danger with this rot-prone genus. Mealybugs can appear. A shrivelled, sunken look usually signals root trouble rather than simple thirst.

Toxicity & Safety

The bishop's cap cactus is not toxic to people or pets, and being spineless it is one of the most hand-friendly cacti to grow - though, as with any houseplant, it is best to discourage pets from chewing it.

Pros & Cons

Pros: striking star geometry, spineless and safe to handle, flowers well for its size, compact and long-lived. Cons: slow-growing, quite rot-prone so needs careful, sparing watering, grown from seed rather than cuttings.

Best Suited For

A superb choice for collectors and anyone wanting an unusual, spineless, sculptural cactus for a bright windowsill - just water it carefully and give it plenty of sun.

FAQ

Is it safe that it has no spines? Yes - astrophytums are naturally spineless, which makes them pleasant and safe to handle.

Why did mine suddenly go soft and collapse? Almost always root rot from overwatering or cold, wet soil - water much more sparingly and improve drainage.