Spring/Summer/Fall Types

CACTUS
Gymnocalycium mihanovichii “Moon Cactus” or “Hibotan”

 

Characteristics of Moon Cactus

The Moon Cactus is a cultivar born from the seedlings of G. mihanovichii “Botandama” cacti. It was originally created in Japan, and now has become popular around the world. This cute and colorful cactus comes in a variety of hues, including red, pink, and yellow. Because this cultivar doesn’t contain chlorophyll, you can’t grow it unless you graft it on to another cactus. Be careful not to overexpose the cactus to direct sunlight, or the plant will sunburn, and give the plant water after the soil has dried.

Points to Check when Buying

Select a Moon Cactus that isn’t etiolated, and where both the stock cactus and cultivar on top are full of energy. In particular, the stock should be green and firm.

Soil Composition

Mix 5 parts small-grain Akadama, 3 parts Kanuma soil, and 2 parts mulch for a ratio that has good drainage, water retention, and breathability. Add a layer of gravel like large-grain Akadama or pumice to the bottom of the pot.

Fertilizer

When you transplant a cactus, add a layer of granular base fertilizer on top of the layer of gravel.

How to Transplant

As the plant grows, its roots will grow to fill the pot and it will become root bound, so you should remove the old soil from the roots, spread the roots apart, and pour in fresh soil. Transplant your cactus every spring.

Pour in the slightly dampened new soil. When you have finished transplanting, lightly tap the pot to level the soil and place the plant in partial shade to take root.

How to Propagate

Many offsets will develop on the side of the Moon Cactus as it grows, so cut them off and graft them to propagate the plant. For stock, use Hylocereus undatus, as shown in the diagram, or Myrtillocactus geometrizans.

Grafting

When an offset develops and grows large on the side of the mother plant, cut it off with a utility knife or similar tool.

Tie the graft and stock together with cotton string pulled taut. Place the plant in partial shade with good ventilation for about a week to bind together.

 

Key Points for Growing Moon Cactus

The splendidly colored Moon Cactus grows by taking nutrients from the stock plant, so the health of the stock is critical. The stock cactus should be a robust species so it will be easy to grow. For example, the Moon Cacti that are sold in plant nurseries mainly use Hylocereus undatus as stock. This is an extremely hardy species, so even if you just use your intuition and give it lots of water when the soil is dry, your stock cactus should grow just fine.

Cultivation Calendar

Succulent Advice Q&A

Q I want to plant the offsets from my cactus as cuttings. Do you have any advice?

A An offset will not grow if you plant it like a cutting. This cultivar doesn’t contain chlorophyll and can’t photosynthesize, so it must be grafted onto another cactus or “stock.” When grafting, it is important to set the vascular tissue of the offset on top of that of the stock. The cells in the cut cross-section of the plant are weak, so be careful not to rub the graft and stock together.

In addition to red and yellow, the Moon Cactus can be seen in vivid pink and orange hues.

This cultivar does not contain chlorophyll, so grow it by grafting it to a green stock plant.

Members of the Gymnocalycium Genus

G. calochlorum

G. saglionis

G. bruchii