Astrophytum myriostigma var. quadricostatum Borg
Accepted Scientific Name
Bishop's Cap Cactus, Bishop's Cap, Bishop's Hat, Bishop's Miter Cactus, Bishop's Hood
Astrophytum myriostigma subsp. quadricostatum, Astrophytum myriostigma var. quadricostatum-pubesente, Astrophytum quadratum, Echinocactus myriostigma subsp. quadricostatus, Echinocactus myriostigma var. quadricostatus
Astrophytum myriostigma var. quadricostatum is a form of Astrophytum myriostigma with four ribs instead of five. It is a spineless cactus with a usually solitary, quadrangular to almost spherical stem when young, becoming columnar with age. The stem is up to 3 feet (90 cm) tall and 4 inches (10 cm) in diameter. Flowers are pale-yellow, up to 2 inches (5 cm) long, and appear in spring and summer.
USDA hardiness zones 9a to 11b: from 20 °F (−6.7 °C) to 50 °F (+10 °C).
How to Grow and Care
Bishop's Cap is one of the easiest Astrophytums to grow. It is sometimes seen as a grafted plant but grows very well on its roots too. Like other star cacti, it does not ask for much water and thrives even with a very small, Spartan root zone. However, they demand fast drainage overall and are downright hard to kill except with excessive moisture and fertile soils. Very slow growth and small size make them ideal for bonsai pots and other creative containers on the porch, window sill, or balcony. This is ideal for beginners due to its lack of thorns, exceptional geometry, and ease of cultivation indoors.
Bishop's Cap is cold hardy to about 20 °F (−6.7 °C). It should be given light shade for best results, although it will tolerate full sun. During the summer, it should be given moderate water, but it should be kept dry as soon as the temperature starts dropping and keep it perfectly dry in winter at temperatures from 40 to 60 °F (5 to 15 °C). Bishop's Cap grows much faster with a low nitrogen content fertilizer in spring and summer.
Learn more at How to Grow and Care for Astrophytum.
This cactus is a form of Astrophytum myriostigma.
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