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Bishop’s Cap Cactus Care – The Definitive Guide

Bishop’s Cap Cactus Care – The Definitive Guide

Want a little cactus with a bit of a wow factor? The Bishop’s Cap Cactus might just fit the brief. This flowering succulent is known under many names.

You’ll see it also advertised in garden centers as the Bishop’ Hood or Bishop’s Hat, as well as its scientific name Astrophytum Myriostigma.

Really easy to take care of, this cactus is blessed with a daisy-like flower at its tip. The star-shaped yellow flower means the Bishop’s Hat has also earned the nickname “Star Cactus”.

The stem is green, but is covered in little white hairs. This gives the cactus a slightly bluey-green appearance.

Let’s find out a little bit more about caring for this cute decorative species. You’ll soon see it is an excellent option, particularly for beginners! 



Bishop’s Cap Cactus Care

The Bishop’s Cap Cactus needs surprisingly little maintenance. Soil should be a specific mix made for cacti – usually potting soil combined with sand. Direct sunlight should be avoided – it will do well in a bright room in indirect light. Watering should be light, and you should aim to keep the soil dry. Keep your cactus in temperatures no lower than 40 degrees Fahrenheit. Avoid also high temperatures too – anything over 60 degrees Fahrenheit. Preferring lower levels of humidity and dry soil you can keep this flowering cactus on your windowsill for hours of enjoyment. 



First time cactus owners often make a dangerous mistake when they take home their first plant and expose it to too much direct sunlight. I’ve made the same faux-pas too! The Bishop’s Cap Cactus is no exception. Just because this cute succulent has its origins in the deserts of Mexico does not mean that it is going to love midday sun.

A young cactus is much better placed in bright, indirect sunlight. That’s actually great news for those of us who love keeping cacti as an indoor houseplant.

The Bishop’s Cap Cactus will do well in a bright room or window ledge where it has access to light.

Don’t risk taking your young plant out to the full midday sun in high summer. They can get sunburn just like any other plant, so take care here. When a little older, they will enjoy a few hours of sunlight but only if introduced gradually and carefully. 



One of the great things about the Bishop’s Cap Cactus is its low water requirement. Extremely drought tolerant, you’ll be able to head off on vacation for a couple of weeks without worry. You can get away with watering the Star Cactus in the summer once a month. In the winter, during the resting period, you’ll hardly need to water them at all.

Under watering is less of a danger than overwatering. If you have neglected the star cactus too much you may see it slump down and develop brown patches. However, your cactus is much more likely to suffer from overwatering.

Never let water pool in the soil, water when the soil is damp, or overwater. The cactus is an easy candidate for root rot if overexposed to moisture. Unfortunately, as root rot happens under the soil, the signs of any damage are not visible until it is too late. Bad root rot is hard to fix, and can bring a high probability of demise. 



Bearing in mind the importance of making sure the roots don’t get wet, you’ll need to ensure the soil too is well-draining. A drainage hole in the pot is not a bad idea as well, to ensure you cover all your bases. For the soil, you can purchase a potting mix specifically made for cacti. You can also make your own if you prefer. Simply mix a standard potting mix with sand or pumice and your cactus will be more than happy with its new environment. 



This cactus can tolerate low temperatures in winter – down to around 40° degrees Fahrenheit. During this stage, the plant will go into a resting period. Make sure you set up the conditions to allow this to happen. During this period, you don’t need to water your cactus, and you’ll need to let the soil dry out. The cactus will be comfortable up to about 68 degrees Fahrenheit.

Don’t let it get excessively warm or expose it to very high temperatures.

Also, do not expose the cactus to any risk of frost damage by accidentally leaving it outside during the winter months.



The adult flower will – from spring through to summer – produce yellow, daisy-shaped flowers. Each individual flower only usually lasts a few days, but the display should continue throughout the summer months. Don’t worry if your cactus doesn’t flower for a few years – this only really happens after maturity is well established. 



The star cactus is not a big fan of humidity. It will be much happier in a drier environment, one that replicates that of its native deserts of northern Mexico. However, as we already indicated, it’s a pretty tough plant. So, it will usually be fine with the humidity levels in a normal apartment or home. We’d recommend keeping it away from the bathroom though!



The Bishop’s Cap cactus cannot generally be propagated by cuttings or offshoots. That leaves really only one way to do it – through seeds. Make sure you are sourcing the seeds from an official supplier – the natural plants in their own environment have been so harvested that there are not many left. Luckily, once you get the seeds it is a pretty easy process. 


Propagation by seed – Step by Step

  • Soil: Get yourself some well-draining propagation soil. A sandy content would be ideal.
  • Planting: Insert the seeds into the soil in a normal manner
  • Watering: You want to keep the soil lightly moist until you get sprouts. You’ll also want to maintain a slightly warm temperature to give the seeds the best chance at taking hold.  
  • Pots: Once you see the sprouts, move the seedlings to their new pots. Keep them exposed to light but out of direct sunlight



Every spring, it is recommended to remove the cactus from their pots and check the roots out. If they are becoming tangled or cramped, they sound like they are in need of bigger environments. If not, simply change out the soil and repot. You may want to add a slow release fertilizer at this point, but generally you won’t need to continue to fertilize the cactus after that.



This little cactus is a slow grower. So don’t expect a huge display immediately. Generally it can grow to up to around 3 feet in height. Expect it to get to around 6-8 inches in diameter. Broken into (usually) 5 sections, the overall shape usually comes out looking like a star.

You will also find some pretty attractive dots along the ridges, almost like the cactus is wearing jewelry. The body will also be covered with a very light bunch of white hairs.

When it flowers, in the warmer months usually, you can look forward to bright yellow, daisy-like blooms. These can become as big as 3 inches. 



Good news for those of you who have curious animals and inquisitive children- the Bishop’s Cap Cactus is not thought to be toxic. Of course, don’t let your little ones or pets near it anyway, just to be safe. 


Common Problems with the Bishop’s Cap Cactus

The Bishop’s Cap Cactus is so easy to take care of! It really would take a lot to kill this plant. In fact, it seems to actually do pretty well when left alone with just occasional watering.

However, there are a few little things to watch out for. Keep them in check and you’ll have a perfectly happy little cactus.  


Root Rot

As with many cacti and other succulents, the Bishop’s Cap Cactus hates to be damp. Whilst the newly potted seedling needs moist soil to sprout, that’s where the damp soil needs to end.

Getting the roots of the cactus too wet, too frequently and for too long will likely result in root rot.

Certainly, you want to keep the soil on the dry side. Fill the soil with too much water and the air pockets that naturally feed oxygen to the root system will get clogged.

Eventually, the affected roots will rot and die. It will also spread to the healthier tissue. Root rot is hard to shift, even if you fix the soil and drainage.

By the time you discover it, it is often too late to correct. By the time the first exterior signs appear – generally demonstrated by yellowing at the base and a “softer feel” – your cactus will likely have no root system left. 


Stem Rot

This is another issue, similar to root rot, which is caused by overwatering. The stem of the Bishop’s Cap Cactus is full of water and it can become an easy breeding ground for fungus. Usually, you can cut out the affected areas, but it can quickly spread.

Make sure you keep an eye on the stem for any signs of fungal infection.

This type of fungal disease can usually happen when the cactus is subject to overwatering. So, that’s just one more reason to keep your soil on the dry side. 


Pests and Insects

The most common undesirable visitor to your Bishop’s Cap Cactus is likely to be a mealy bug. These guys penetrate the plant and spread infections. If you catch sign of any unwanted pests on your cactus, remove or spray them off immediately. If you get repeat infections you may want to treat with an insecticidal spray or soap wash. 



The Bishop’s Cap will rarely need much attention. You’ll be able to head off on vacation for a couple of weeks without worrying. But it could happen, especially if you leave it for long periods over the summer months. Signs of over watering can include brown spots and the cactus losing its overall upright shape. 



Make sure that your new cactus is not exposed to direct sunlight. Just because the deserts of Mexico are their native habitat, doesn’t mean you want to scorch them. Too much direct sun exposure will cause unsightly burnt patches on your beautiful cactus.

The good news about sunburn is that, whilst the affected bits won’t regenerate, any new growth will largely be unaffected. 

Frequently asked questions about the Bishop’s Cap Cactus


Can I go on holiday without watering my Bishop’s Cap?

Sure! The Bishop’s Cap doesn’t really like too much water. It can survive for several weeks without it, and is pretty drought tolerant. Don’t abandon it completely though! 


Why is my Bishop’s Cap Cactus not flowering?

This cactus flowers only after maturity. In some specimens, this can take up to 5 years! As with growth, patience is key with flowering. Stick at it and you will be rewarded eventually. 


My Bishop’s Cap Cactus is soggy to the touch! What happened?

Hmm. Check your soil. If it is too moist, soggy, or shows signs of water pooling in it, you have a problem. If the lower part of the stem or the upper part of the base are showing softness to touch you may have either root rot of stem rot. Act quickly to save your cactus as it can rapidly destroy the plant. 



If you are looking at getting into keeping cacti, then the Bishop’s Cap is perhaps a good one to start with! So easy to care for and very quirky in appearance, it’s a great choice.

Follow the care tips in our guide and you can expect to get great enjoyment from both the cactus and its flowers. 

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