Astrophytum Myriostigma Var. Onzuka | Amazing Cactus |

Astrophytum myriostigma var. onzuka are hailing from Mexico. Their natural habitats would usually be the stony and limestone soil which would be about 1500m in altitude.

A Japanese called Tsutomu Onzuka has created this cultivator and it belongs to the Cactaceae family. This is one of the most sought-after plants.

Astrophytum myriostigma var. onzuka

The Astrophytum myriostigma var. onzuka epidermis is the highlight of these plants. Above all, their ability to flower makes them more extraordinary.

If you were wondering, start gardening with a cactus, Astrophytum myriostigma var. onzuka would be the one for you as they are great starter plants.

If you are willing to learn on the growth tips of the plants, the bugs and the pests attacks they may come across during their growth I suggest you read this article. Furthermore, I will be covering the modes of propagation as well.

How do I identify Astrophytum myriostigma var. onzuka?

The identification of Astrophytum myriostigma var. onzuka is fairly simple as they have some features which are unique to them.

Astrophytum myriostigma var. onzuka plants usually grow solitary. Further their stem would tend to take a barrel shape.

Those stems would be prominent in bluish green in color. Further Astrophytum myriostigma var. onzuka stem would come up with about 5 ribs too.

As described in the above, the Astrophytum myriostigma var. onzuka epidermis is the main focus of the plants.

You could see the epidermis carrying many little white dots which would cover the stem. That gives them a look of a white stone.

Astrophytum myriostigma var. onzuka is a breathtaking hybrid plant and they are well known for their snowy white markings.

Apart from these characteristics, Astrophytum myriostigma var. onzuka plants emerge with blossoms in yellow.

They would tend to take a funnel shape and would arise right at the top part of the stem. Astrophytum myriostigma var. onzuka blooms are fairly big and you could spot the bearing flowers during spring.

Astrophytum myriostigma var. onzuka stems would reach a maximum height of 90 cm at maturity. Further they would be 5-10 ( 20cm) broad too.

Growth rate

Astrophytum myriostigma var. onzuka are a slow growing set of plants.

One look care guide

Botanical NameAstrophytum myriostigma var. onzuka 
Plant TypeCactus
Mature Size90 cm tall / 5-10 ( 20cm) wide
Sun ExposureFull sunlight
Soil TypeWell draining
Soil pHNeutral 
Bloom TimeSpring
Flower ColorYellow
Hardiness ZonesUSDA hardiness zones 10a to 11b: from 30 °F (−1.1 °C) to 50 °F (+10 °C).
Native AreaMexico
ToxicityNon Toxic
Average price $ 13

How do you take care of Astrophytum myriostigma var. onzuka?

Light Requirement 

Astrophytum myriostigma var. onzuka would flourish as long as they get bright indirect sunlight. Best recommended is to avoid exposing them to direct bright sunlight during the hottest parts of the day particularly during summer.

See also  7 Super Cute Facts About Beautiful Kalanchoe Marnieriana Flowers

When you cultivate them indoors, I recommend placing them at the brightest sunny spot at your home which would most probably be a bright sunny windowsill.

If the plants are lacking ample sunlight, best is to grow lights closer to the plants which will enhance the sunlight. in addition to that you need to choose a spot where they will be secured from direct sunlight when you grow them outdoors.

Astrophytum myriostigma var. onzuka

Temperature and humidity

Astrophytum myriostigma var. onzuka plants are not tolerant of temperatures which drop to 7 degrees and below.

If you expose them to colder conditions than that, chances are that it may result in health deterioration of the plants. What you could ideally do is bring them indoors whenever the weather gets too colder. 

Is it cold hardy?

Astrophytum myriostigma var. onzuka are not frost hardy plants. As aforesaid, whenever there is a forecast of extreme colder conditions, you need to bring the plants indoors to protect them from those unhealthy conditions.

Growth Zone

Astrophytum myriostigma var. onzuka would grow vigorously in USDA hardiness zones 10a to 11b: from 30 °F (−1.1 °C) to 50 °F (+10 °C).

Watering Requirement

Accurate watering is one of the most crucial factors when you look after these plants well.

Astrophytum myriostigma var. onzuka are quite responsive towards excess watering and you should never expose them to waterlogged soggy conditions when you grow them.

If I further elaborate on this, you need to water them moderately during spring and summer once every week.

However, you need to water the plants only if the soil is dry from the previous watering session only. Do not apply any water when they are dormant.

See also  How You Should Use 13 USDA Hardiness zones For Succulent Gardening

Over watering would make your plants susceptible for fungal attacks and for the rest of other bacterial attacks as well. In addition to that it would pave the way for root rot too.

Soil Requirement Type / pH.

A soil mix which is fast draining would be excellent for the Astrophytum myriostigma var. onzuka healthy growth.

Once you use a fast-draining soil mix, it would ensure that all excess water would move out from the soil without retaining.

Consequently, it would avoid any probability of root rot taking place. In addition to the fast draining, it is important that your selected soil mix has a good aeration as well.

So, a commercially made succulent or cactus soil mix fulfills both these requirements and the easiest option would be to go ahead with that.

However, you may make a soil mix on your own by mixing regular soil mix into pumice and clay too. These substances are crucial in enhancing the draining of the soil mix.

Pot size Potting and Repotting

Choose a pot which has one or two draining holes to grow these plants. Besides, I suggest you go for a porous material pot also as then it would allow all excess moisture to evaporate faster in those pots.

On the other hand, when it comes to repotting the plants, you can consider repotting them when they become too big for the older pots.

Ideally when you transplant them you should select a pot which is about 3 cm wider than the older pot. I suggest you repot the plants during their growing season whilst using a fresh soil mix.

Fertilizer and time of year

Astrophytum myriostigma var. onzuka are slow growing plants and they don’t require heavy feeding.

However, if you wish to feed them with a fertilizer when they are actively growing, it will allow them to stimulate the growth of them. You can apply the fertilizers just once a month. Never feed them in winter as by then they will be dormant.

See also  Why Succulents Grow Tall or Stretching? Full guide | Succulents That Grow Tall


Astrophytum myriostigma var. onzuka produces flowers in yellow. They would emerge with flowers during the spring season usually. Those flowers look like funnels.


Astrophytum myriostigma var. onzuka are winter dormant plants.


Astrophytum myriostigma var. onzuka has no reports of its toxicity.

Astrophytum myriostigma var. onzuka

Common bugs and illnesses

Astrophytum myriostigma var. onzuka roots are prone for root rot, especially when you expose them for waterlogged and soggy conditions.

In fact, over watering could pave the way for so many issues in the plants. They would make your precious plants more vulnerable for pest’s attacks as well.

For example, mealy bugs, spider mites and aphids would tend to infest these plants whenever they find attractive conditions for them.

How to propagate Astrophytum myriostigma var. onzuka 

There are several ways of propagating the Astrophytum myriostigma var. onzuka plants, for instance you may use either stem cuttings or seeds to propagate them. Besides, you could use the grafting method also to make new plants. 

If you wish to propagate the Astrophytum myriostigma var. onzuka using stem cuttings, you need to first get the cuttings during spring and allow them to dry.

Bear in mind to use all sterile tools to make the cuttings unless chances are that it may result in unwanted infections in the plants. 

Once the cuttings are withered and calloused, you could simply place them in a sandy well-draining soil mix.

I suggest you use multiple cuttings for this purpose so that there will be a high probability to succeed. A temperature around 20 degrees Celsius would perfectly fit in for this.

On the other hand, when you use the seeds propagation method, you need to simply sow the seeds in a sandy soil mix whilst ensuring there is a high humidity level and a temperature around 14 degrees Celsius.

Lastly if you wish to practice the grafting method, you need to first select a stock which is equal to the diameter of your cut section.

Once you cut them, remove the latex entirely. Next bring the scion to the stock and keep them enclosed by using an elastic band. Keep the plant in a dry and a shady place for about 10 days and then remove the bands.


To recap what we covered here, Astrophytum myriostigma var. onzuka plants are such a versatile hardy set of plants which would adore the entire space. So, hurry up and grab your Astrophytum myriostigma var. onzuka plants and start growing them !

Credit to : Cactaceae Review
Read Next : Astrophytum Myriostigma Var. Nudum | A Unique One |
About author

I’m Dr. Chamika, As a hobby love talking about plants and showing you that taking care of indoor plants. My website is knowledge I’ve learned over the years and continue to learn about growing succulents. If you’re a succulent lover, then you have come to the correct place.