Astrophytum Myriostigma Guide: How to Grow & Care for “Bishop’s Cap Cactus”

Our Guide to Astrophytum Myriostigma - Everything you will ever need to know! Tips for planting and caring for “Bishop’s Cap Cactus”
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Oh, what do we have here? A passionate gardener that could not resist the temptation of buying another cactus? Well, we sincerely empathize with you! This cute star-shaped cactus and its beautiful flowers can steal anyone’s heart in just a second. Want to know more about this eye-catching mix of patterns and colors? Say no more!

Astrophytum myriostigma, otherwise known as the Bishop’s Cap Cactus, Bishop’s Miter Cactus, or Bishop’s Hat, is a species of flowering cacti in the Cactaceae family. This adorable cactus can be found chilling in the highlands of central and northeastern Mexico.

Bishop’s Cap cacti are sometimes sold as grafted plants, but they can also grow pretty well on their roots. With their lovely varieties and easy-going style, these cacti are a must-have in every cacti-lovers collection. They are suitable for both indoor and outdoor growing, but you will see them grown more often as houseplants on windowsills, desks, or bookshelves in different minimalist decorations.

About Bishop’s Cap Cactus

  • Their botanical synonyms include Echinocactus Myriostigma, Astrophytum Columnare, A. Nuda, A. Prismaticum, and A. Tulense. They might be still found in shops and nurseries by these names.
  • When looking at these cacti from above, they look very similar to the shape of a star. This is also the origin behind their genus name “Astrophytum”, which is the Greek for “star plant”.
  • Thanks to their peculiar appearance and mesmerizing flowers, Bishop’s Cap cacti have gained the Royal Horticultural Society’s Award of Garden Merit.
  • In their native habitat, these cacti grow at elevation levels of 2500 to 5000 feet (762-1524 m) above the sea level. They are used to stony and calcareous soils.
  • As Bishop’s Cap cacti grow older and taller, their ribs covered in white and hairy spots resemble the traditional headdress worn by bishops. This is the main reason why they are sometimes called the Bishop’s miter.
  • They do best in environmental conditions that simulate their natural habitat. If planted in a cactus mix and placed in a bright and warm location, these cacti will be more than grateful.
  • Bishop’s Cap cacti are susceptible to root rot, so you must be careful not to over-water them. They also need protection from any humid environment.
  • These spineless cacti have no toxic effects known. They can be grown safely around playful pets and children, although consuming them is not recommended.
Astrophytum Myriostigma
Astrophytum Myriostigma

Bishop’s Cap Cactus Features: An Overview

  • They belong to the Astrophytum genus that contains exactly six species of gorgeous cacti. The species cultivated as houseplants are commonly referred to as the Star cacti.
  • Bishop’s Cap cacti is a pretty large species that can reach between 2.3 and 3.3 feet (70-100 cm) in height and about 4 to 8 inches (10-20 cm) in diameter.
  • These bloaty cacti can consist of three to seven pronounced, succulent, and vertical ribs. Usually, they have five ribs that present no spikes.
  • In their natural habitat, the globular to cylindrical-shaped stems are covered with a white mob of trichomes. Some horticultural varieties may lack these dots.
  • When growing in the wild, Bishop’s Cap cacti produce flowers in early spring to allow their seeds to grow under the summer rains. In cultivation, these plants may bloom during the summer.
  • These cacti exhibit one or more superb bloomings of 1.6 to 2.4 inches (4-6 cm) in width near the apex. They may take up to six years to bloom.
  • Their flowers come in various shades of creamy white, yellow, or violet-pink with their base and center colored in creamy yellow, orange, or red.
  • If the flowers are pollinated, they turn into small, hairy, and reddish fruits that measure about 0.8 to 1 inches (2-2.5 cm) in diameter.

Growing Bishop’s Cap Cactus

Like all cacti, these lovely specimens need lots of light to grow healthy and happy. Bishop’s Cap cacti can be grown in full sunlight only if you live in a region with cooler climates and a sun that is not too harsh. These cacti thrive in bright and indirect light when they are exposed to it for at least six hours daily. When growing them indoors, place your cacti near south-facing windows and protect them from direct sunlight using sheer curtains.

Bishop’s Cap Cactus
Bishop’s Cap Cactus

Bishop’s Cap cacti do well in slightly cooler to mid-warm temperatures that range from 50 to 68 °F (10-20 °C). They are somehow cold hardy to temperatures that drop to 20 °F (-6.7 °C), but will eventually die off when they are exposed to long periods of frost. In winter, it is better to bring your cacti inside if you grow them outdoors.

Planting Bishop’s Cap Cactus

They will have a great time if planted in soil with excellent drainage and a pot that has drainage holes at the bottom. Bishop’s Cap cacti are native to rocky terrains, so they will show the best results in a commercial potting mix that is designed for cacti and succulents. You can also prepare your own mixture by combining a quarter of coarse sand, a quarter of pumice, and half potting soil. Make sure you protect the neck of your cacti by spreading a layer of sand above the potting mixture you are using.

Bishop’s Cap cacti don’t need much to thrive and they can spend their life without any fertilizers. However, if you want to spoil them once in a while, the ideal time for fertilizing is from summer to the first signs of winter settling in. Feed your cacti with a diluted liquid fertilizer that is low in nitrogen once every month.

Astrophytum myriostigma, From Amazon

These cacti have a small root zone, so they are best grown in tiny pots. When Bishop’s Cap cacti start to outgrow their containers, it may be a great time for repotting. Just keep in mind that they handle repotting better in early spring when they are the most vigorous. Look for a pot that is one size larger than the current one, fill it with fresh potting mix, and transplant your cactus carefully.

Bishop’s Cap cacti may be bothered by pests like mealybugs and scale insects during the cooler months. If you notice any web-like coating or other signs of infestation, you can treat the affected parts with a cotton pad dipped in rubbing alcohol.

Watering Bishop’s Cap Cactus

If you already have one or more cacti around your house, you will know how often a Bishop’s Cap cactus becomes thirsty. For a beginner gardener, however, things may be different. But no worries! These cacti do not need water as often as you do, so it will be very easy to get along with these little ones. Delightful, isn’t it?

Like most cacti, Bishop’s Cap beauties prefer to receive less water than the experience of soggy conditions or over-watering. During the summer, these cacti require water only when the soil has dried out completely. The best way to help them accommodate with new environmental conditions is to begin watering sparingly in early spring then slowly increase watering as temperature rises.

When the winter has settled in, you can skip watering for good at temperatures that range from 40 to 60 °F (5-15 °C). Moreover, if the temperatures get cooler, you can start to water your Bishop’s Cap cacti less often from mid-autumn. Make sure you decrease the frequency of watering until March or when the temperatures are slightly warmer.

If your Bishop’s Cap cacti are exposed to high levels of humidity, they may become tender and eventually die off. To maintain dry air around these plants, you can use a dehumidifier or simply place them in a room with air vents.

Astrophytum myriostigma
Astrophytum myriostigma

Propagating Bishop’s Cap Cactus

What a nice-looking specimen to have around! And why not sharing some babies with your friends or a beloved one? Bishop’s Cap cacti can be easily propagated through seeds and show beautiful growth no matter how experienced you are in the garden. No, don’t you dare to buy some seeds from markets! Their seeds can be collected from dried flowers and planted in the blink of an eye, making this process more simple than it seems.

The most important detail in this method is the propagating medium. Bishop’s Cap seeds require sandy and well-draining soil to germinate properly, so look for a suitable growing environment right away! Once you have found the best potting mix, you can remove the fresh seeds from their flowers. Fill a container with potting soil and press the seeds in the soil gently. For optimal results, you must maintain the soil temperature at around 78 °F (26 °C). Place the pot in a warm and humid environment and provide the seeds with light moisture.

When you notice signs of germination and little growth, your baby Bishop’s Cap cacti are ready to be transplanted into their individual pots. It is suggested you plant your babies in a mixture of half potting soil, 25% pumice, and 25% pumice with a thin layer of sand over the potting mix. Keep the baby cacti in a slightly warm location with bright, indirect light and protect them from extreme environmental conditions.

In Conclusion

Impressed already? Wait to see how stunning your Bishop’s Cap cacti will look with proper care and lots of love! All you have to do is to provide them with bright light, warm temperatures, and watering once in a while and your plants will be more than happy. Plus! If you are patient enough, these beauties will stay by your side forever and even thank you along the way through cute flowers. Worth it!

Are you growing Bishop’s Cap cacti? Share your experience with us in the comments!

Miruna Secuianu

Miruna is an experienced content writer with a passion for gardening. She is the proud owner of an outdoor rose garden and an indoor collection of tiny succulents. She bought her first succulent 10 years ago - an adorable Echeveria Setosa. Now she owns more than 100 succulents and cacti of different colors, shapes, and sizes. Miruna is a versatile writer and, as you might have guessed, her favorite topic is gardening. Contact

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