Magical ‘Moon Cactus’: Gymnocalycium Mihanovichii and 4 Things to Know About It

Gymnocalycium mihanovichii, also known as the ‘Moon Cactus’ or Hibotan cactus, is a small cactus native to South American deserts in places like Brazil and Argentina. It is usually seen as a grafted cactus, meaning that it has been attached to a host plant as the common, bright neon colors are unable to photosynthesize on their own. Grafting enables its vascular system to obtain nutrients from a host plant, but it also makes it less hardy and typically only lasts for six months to a year.

Cactus with red top moon cactus

How Much Sunlight Does a ‘Moon Cactus’ Need?

‘Moon Cactus’ should be kept indoors near a bright window or in a greenhouse situation. They need to be kept in bright shade with 1 to 2 hours of slanted sunlight daily, depending on where you live. It’s important to protect them from intense sunlight as they are sensitive to light and can get sunburned. They also do not do well in cold temperatures and should be protected from frost. It’s worth noting that moon cactuses are not known to grow much, if at all.

Grafted cactus care moon cactus

How Often Should You Water a ‘Moon Cactus’?

Moon Cactus (Gymnocalycium mihanovichii) is a low-maintenance cactus that is popular for its vibrant colors and unique appearance. However, it can still face issues if it is overwatered. Overwatering can cause the roots to become waterlogged, leading to root rot and other problems. Signs of an overwatered cactus include yellowing of the stem, a soft and mushy stem, and an unpleasant smell coming from the soil. If you notice any of these signs, it’s important to adjust your watering habits and allow the soil to dry out completely before watering again.

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In addition to proper watering, Moon Cactus also benefits from occasional fertilization. However, it’s important to use a fertilizer specifically formulated for cacti and succulents and to follow the instructions carefully to avoid overfertilization. Too much fertilizer can lead to burned roots and other issues, which can be just as damaging as overwatering.

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Gymnocalycium mihanovichii care moon cactus

How to Propagate a ‘Moon Cactus’

Propagation of ‘Moon Cactus’ can be done by taking offshoots from the colorful part of the main ‘Moon Cactus’, which must be grafted onto another cactus or “rootstock.” This can be done by cutting off the top piece of the cactus and then cutting off the top of the rootstock, placing the cut ends together, and holding them in place with rubber bands or string. It usually takes around 6-8 weeks for the two plants to grow together as one.

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Pink moon cactus care moon cactus

Gymnocalycium mihanovichii ‘Moon Cactus’ is a highly variable cactus, with many different varieties described. In cultivation, it is common to find mutants of cultivated individuals that are only able to survive when grafted onto another plant due to their lack of chlorophyll, which is necessary for photosynthesis. These spectacular mutants typically have vibrant neon red, orange, pink or yellow pigments that are only viable when grafted on top of another succulent plant such as Hylocereus. These mutant cultivars are particularly popular among growers. However, it’s important to note that these mutants will not survive as seedlings unless they are grafted onto another cactus with normal chlorophyll.

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Ruby ball cactus moon cactus

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Common Problems with ‘Moon Cactus’

Common problems with ‘Moon Cactus’ include sunburn, which can be identified by beige patches on the plant, and root rot, which can occur from overwatering. If the lower part of the stem softens, it’s likely due to rot. It’s also worth noting that moon cactuses can be harmful because of their sharp spikes and should be kept away from pets. They are also tricky to propagate yourself and don’t last long.

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Red moon cactus moon cactus

In summary, Gymnocalycium mihanovichii, or ‘Moon Cactus’, is a small cactus native to South America that is grafted onto a host plant in order to obtain nutrients. It needs indirect sunlight, with 1 to 2 hours of morning or afternoon light, whether in a shady area that’s still bright or near a bright window. It should only be watered every 2 weeks, allowing the soil to dry between waterings. Propagation can be done by taking offshoots and grafting them onto another cactus or “rootstock.” Common problems include sunburn and root rot. They are also tricky to propagate yourself and don’t last long. They also can be harmful because of their sharp spikes and should be kept away from pets.

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Gymnocalycium mihanovichii hibotan moon cactus
This type of ‘moon cactus’ doesn’t need to be grafted onto a rootstock as it has chlorophyll to photosynthesize sunlight.

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