Actual size and flowering may vary slightly based on season.
Bishops Cap Cactus
Bishops Cap Cactus is a spineless star cactus with a few broad ribs that give it the shape of a bishop's hat. The green body is dusted with tiny white flecks that make it look speckled from a few feet away. Glossy, sweet-scented yellow flowers open at the top through summer, even on small plants. It grows slowly and suits pots and rock gardens.
Best for: patio pots, rock gardens and beds near seating, where a cactus without spines is welcome.
It has no spines, so it can sit in a pot by a bench, doorway or path where a spiny cactus would be a problem. Handle it gently anyway, since the white flecks rub off.
It blooms readily at about 2 inches tall, so a small potted plant can flower. Use a gritty cactus mix and a pot with a drainage hole.
The broad ribs make a star shape from above, and the speckled body stands out against gravel and darker rock. It grows slowly into a short column over many years.
It rots if the soil stays wet in fall and winter, so it needs a dry winter rest. It can be damaged below about 20°F.
- Closer group4 in apart
- Looser group8 in apart
Wait about a week after planting before the first water. Water a potted plant about weekly in hot weather, letting the mix dry between drinks. Stop by October and keep it dry through winter.
It grows in full sun to all-day light shade. In the Valley, light shade in summer keeps the color richer.
It can be damaged below about 20°F. On frost nights, cover it with frost cloth or a sheet that reaches the ground, not plastic, and take it off in the morning. Move pots under a patio roof.
Feed a potted plant with a weak liquid fertilizer about monthly from April through September. Skip feeding in the ground.
Drainage test first. Dig the hole and fill it with water. If water is still sitting in the hole a day later, you likely hit caliche, clay or hard soil, so fix the drainage before planting. If it drains very fast, the soil is sandy. Standing water around roots is a common reason new plants fail.
Weed cloth. Cut it away from the planting hole and where the roots will spread. Remove any plastic sheeting completely, since it keeps water and air out of the soil.
Rock or decomposed granite with no soil underneath. Bring in soil close in texture to your native soil, mix it with the soil below, and build up enough depth for roots before planting.
If you can break through. Use a breaker bar, pick, or jackhammer. Dig through the caliche and break out the solid chunks. Backfill with the soil you dug out, with no compost or manure in the hole. Confirm drainage before planting.
If you cannot break through. Dig narrow holes through the hard layer beside the root ball, not under it, and refill them with the same soil, not gravel. If it still will not drain, plant on a low mound of the same soil.
Root ball. Check the outside edges for any roots circling around. Loosen or cut those so they grow outward. Do not break up the center of the root ball.
Depth. The top of the root ball should sit at or just slightly above the surrounding soil level. Planting too deep can lead to rot and kill the plant.
Drip emitters. At planting, put the emitters on the root ball, on different sides of the plant. After about 2 months, move them to the outer edge of the root ball. Over the first year, add emitters farther out toward the edge of the branches as roots grow. Once a plant is rooted, never water only at the trunk.
Does bishops cap cactus have spines?
No. It is a spineless cactus, so it is a good pick near seats and walkways. The white flecks on the skin are tiny scales that can rub off, so handle it gently.
How big does it get?
It grows slowly to about 1 to 3 feet tall over many years, with a body about 8 inches wide. It starts round and becomes a short column with age.
When does it bloom?
Glossy, sweet-scented yellow flowers open at the top through the summer. It can bloom when only a few inches tall.
Does it need full sun in Phoenix?
It grows in full sun to all-day light shade. Light shade in the Valley summer keeps the color richer and prevents scorch.
How often should I water it?
In a pot, water about weekly in hot weather and let the mix dry between drinks. Stop watering by October and keep it dry through winter, since wet cool soil rots it.
How cold can it take?
It is usually rated to about 20°F for short cold spells. On frost nights, cover it with frost cloth down to the ground, or move a pot under a patio roof.
Should I fertilize it?
Feed a potted plant with a weak liquid fertilizer about once a month from April through September. Plants in the ground do not need it.
What is the white on my bishops cap?
The white specks are natural flecks of tiny woolly scales. They are part of the plant, so there is nothing to treat.
Bishops Cap Cactus for sale in Arizona, delivered to you
Bishops Cap Cactus (Astrophytum myriostigma) is a spineless star cactus from the Mexican highlands. This page covers its size, flowers, sun, water, winter rest and cold in a Valley yard or pot.
Sourced from trusted Arizona growers and delivered directly to your door, job site, or property. We deliver across the Valley and to nearby towns, and quote delivery anywhere else in Arizona.
Why is it called bishops cap?
Its few broad ribs give the plant the outline of a bishop's hat, and it looks like a star from above.
Is bishops cap cactus spineless?
Yes. It has no spines, only tiny white flecks on the skin, so it works near seats and paths.
Bishops cap cactus flowers
Glossy, sweet-scented yellow flowers open at the top through the summer, and young plants bloom too.
Watering bishops cap in the Valley
Water a potted plant about weekly in hot weather. Stop by October and keep it dry until spring.
Is bishops cap cactus cold hardy?
It is usually rated to about 20°F for short spells. Cover it on frost nights.
How big does bishops cap cactus get?
It grows slowly to about 1 to 3 feet tall and about 8 inches wide over many years.
We deliver across the Valley, from Phoenix, Scottsdale and Mesa out to San Tan Valley, Maricopa and Casa Grande, and up to Prescott, Sedona, Payson and Globe. See delivery areas and rates.