Melocactus Rubrispinus | Cactus With Weird Head |

Melocactus rubrispinus are endemic plants to Brazil and to South America. You can spot them at altitudes above 450-870 meters above sea level.  This cactus is under extinction mainly due to human consumption and due to agriculture. Melocactus rubrispinus are wonderful plants to have and you will find this article useful if you are interested in growing these beauties.

We are going to discover the right care tips you should practice when looking after them. Moreover , you will discover how to propagate them, and the common illness and bugs attacks they may come across. So, brace yourself and get ready to learn on the Melocactus rubrispinus cactus!

Melocactus Rubrispinus

How do I identify Melocactus rubrispinus?

This cactus comprise a green to blue green body along with brown, pink, gray spines. 

It has a stem which is depressed and globose to cylindrical in shape. They would be 15-cm in height. Further they would be 14-22 cm in diameter as well.  Besides, they may carry 9-15 acute ribs as well. they would be triangular in shape. Melocactus rubrispinus cephalia would be 10-18 cm in height and it would be 7-12 cm in width.  Melocactus rubrispinus cephalia would carry red bristles along with creamy white wool. In addition to these features, they may carry white wool areoles at first. However, as they grow on, they will almost be naked. 

Melocactus rubrispinus have brownish red spines. Moreover, they will have about 1-6 central spines which form in an erecting manner. 

They would be 17-33 mm in length. Chances are that they would grow occasionally curved downwards too. Melocactus rubrispinus may further carry about 7-10 radial spines as well. They would be about 21-33 mm in length. Besides all these, they produces flowers which you can spot in red from outside and deep magenta within. 

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They would be 20-27 mm in length and 6-9mm in width. They would produce flowers from spring to summer. Further those flowers will form late in the afternoon. Melocactus rubrispinus produce a fruit item which is short, and club shaped. They would be ,1,2-2 cm x 7-12 mm. Moreover, they would be either pure white or pale pink.

Growth rate

This cactus are a fast growing set of plants given that they get best growing conditions.

One look care guide

Botanical NameMelocactus rubrispinus
Plant TypeCactus
Mature SizeMaximum height of 10-18 cm and it 7-12 cm in width
Sun ExposureFull sunlight to partial shade
Soil TypeWell draining
Soil pHNeutral
Bloom TimeSprung to summer
Flower ColorRed to deep magenta
Hardiness ZonesUSDA hardiness zones 10-12
Native AreaBrazil and to South America
ToxicityNon Toxic
Average price 8 USD

How do you take care of Melocactus rubrispinus?

Light Requirement

Melocactus rubrispinus want to have bright sunlight.

However, they do not want as much light as the other arid cactus want. The exposure for strong sunlight would turn them into bronze. Further , it is essential for flower blossoming and for heavy spine production as well.

Temperature and humidity

Melocactus rubrispinus are not tolerant of cold. In fact, they cannot withstand even the fairly colder temperatures. Hence ensure that you always keep them exposed to temperatures above 8-12 degrees Celsius. If you expose them to warmer temperatures throughout the year, it will allow the plants to succeed. Ideally for a minimum temperature of 12 degrees Celsius – 20 degrees Celsius would work well with them.

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Is it cold hardy?

Melocactus rubrispinus are not cold hardy plants.

USDA Hardiness Zone

Melocactus rubrispinus prefer to grow in USDA hardiness zones 10-12.

Watering Requirement

You should ensure that you water the Melocactus rubrispinus moderately. Never leave them to be bone dry as it would be unhealthy for them. On the other hand, excess water will also be unhealthy for them. Melocactus rubrispinus have a weak root system and it is for root rot. They cannot suck water from wet soil. Hence it is very important that you allow the soil to become dry between two watering sessions.

Soil Requirement Type / pH.

Melocactus rubrispinus prefer to have a standard cactus soil mix to thrive well. That is purely because these are porous soil mixes, and they would drain away the excess moisture without retaining them in the substrate. Moreover, they provide a good aeration for the plants root as well.

Pot size Potting and Repotting

A pot which has sufficient draining holes would be optimal for the Melocactus rubrispinus healthy growth. Repotting wise, I recommend doing it once every two years as they have a weak root system, and they need to have a long time to reestablish.

Where to Plant 

Make sure you plant them in a spot where they can gain strong sunlight levels as it will have a great impact on the plant’s vigorous growth.

Fertilizer and time of year

You can skip feeding them if you have grown them in a fresh soil mix and if you had repotted them recently. However , you can consider feeding them during summer as they will be actively growing in summer. Suspend feeding them during their dormancy.

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Melocactus rubrispinus produce flowers in red and in deep magenta. They would be 20-27 mm long and 6-9mm broader. Spring to summer would be their flowering seasons. They will bloom late in the afternoon.


Melocactus rubrispinus will be in dormancy during winter.


Melocactus rubrispinus are nontoxic plants.

Common bugs and illnesses

Melocactus rubrispinus cactus are prone for pests’ attacks for diseases like root rot. You can commonly spot domestic pests such as red spiders, mealybugs, sciara flies attacking these plants. However, if you ensure that you provide them with the right growing conditions, you will hardly come across these conditions.

All you need to do is to provide a soil mix which is explained in the above and water them well and grow them in a pot which has sufficient drainage.

How to propagate Melocactus rubrispinus

You can propagate the Melocactus rubrispinus by seeds. You can simply sow them in February to March in a light sandy soil mix which has a high porosity. Next cover the germination tray with a glass so that you can avoid it withering. The right temperature which would suit this would be 18-22 degrees Celsius.


To conclude, Melocactus rubrispinus are such great plants to have and if you ensure that you provide all good care treatments, they will flourish and perform to their best. So, grab your Melocactus rubrispinus and start gardening and undoubtedly you will love that experience.

Credit to : Plants and Lucia
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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.