Synonyms:

Astrophytum myriostigma
Astrophytum prismaticum
Cereus callicoche
Echinocactus myriostigma

Habitat:

A. myriostigma is native to Mexico Northeast. The plant grows on stony and limestone soils and can spread up to 1500 m of altitude. The cultivar Onzuka has garden origin and was created in Japan by Tsutomu Onzuka (hence the name).

Description:

A. myriostigma is a gorgeous very sought after succulente belonging to the Cactaceae botanical family. The cactus is solitary and the stem is barrel-shaped, bluish-green in color, made of 5 ribs. The main characteristic of this plant is its epidermis: the epidermis is painted with many little white dots that cover almost all the stem and give the plant a fascinating look resembling a white stone. In this genus you can find many different plants changing for color, size, shape and texture but Astrophytum myriostigma cv. Onzuka is one of the most spectacular hybrid for the arrangement of the snowy-white markings. There is also a 4 ribs cultivar called “quadricostatum” and a crested and a variegated form. The crested form usually grows in the shape of a fan and can branches at the base. The forma crestata is a natural mutation that occurred in the A. myriostigma population and that was selected and propagated vegetatively. Blooming occurs in autumn and blossom are borne at the top of the stem. The flowers are large, yellow, funnel-shaped.

Cultivation:

The plant has a slow growth rate but it easy to cultivate. The best sun-exposure is in bright place but is recommended to avoid direct sun-light in the hottest periods. The minimum temperatures that the plant can withstand are 7 ° C, below this temperature it begins to suffer so it needs to be placed indoors in the coldest periods. The perfect soil is a well-drained soil that let the water to drain away and avoid root rot. To achieve this feature, you can mix the pumice soil, clay and soil. Remember to use a perforating pot to drain excess water. Watering can be done regularly in Spring and Summer: during the vegetative period you can water the plant (every 7 days), checking that the soil is completely dry before watering again; in winter you should stop the watering to allow the plant to enter dormancy. If you want a faster and lush growth you can fertilize the plant once a month during the growing season with the specific fertilizers for succulents; stop fertilizing throughout the winter. If the pot starts to be too small for the plant you can repot the plant in a pot 2 cm wider. Repotting should be done early in the growing season with fresh new potting soil. Be careful to red spiders and mealy bugs. The epidermis of ONZUKA is harder than in the normal myriostigmas and cracks easily if plants are overwatered

Propagation:

Propagation can be done by cutting, by seed or by grafting. By cutting you can make the cut during the spring and then let the cutting dry; after a few days the cut surface will dry and a callus will form, then place the cutting in a mixture of sand, soil and pumice. To increase the success of propagation you can make two or more cuttings at the same time. For cuttings it is recommended temperatures around 20 °C. By seed it is very simple to propagate the plant, it is enough to sow the seed in a sandy loam soil and keep it with a high level of humidity and at temperature of 14 C°. By grafting you can make the cut as close to the growing tip as possible, then chose a stock with a diameter similar to that of the scion. After the cut, wash away the latex until it no longer remains. Bring the scion closer to the stock and held together with elastic bands. The plants should be left in an airy and shady place for 7-10 days before the bands are removed.

Curiosity:

The name comes from the greek “Aster”, that means star, and it is given by the presence of several sections that form the pointy ends (from four to eight points) of these plants and that is particularly striking when seen from above.

Official Web Site:
www.giromagi.com

Italian Blog:
www.giromagicactus.com

Tips:
Read our advice