Astrophytum MYRIOSTIGMA 'COLUMNARE'

Astrophytum MYRIOSTIGMA 'COLUMNARE' - Columnar bishop's cap 'Columnare', Astrophytum myriostigma 'Columnare', Bishop's cap cactus.

Astrophytum is a genus of succulent plants in the cactus family (Cactaceae), including 6 species and numerous varieties and forms growing on rocky and calcareous soils in the foothills and mountains of northeastern Mexico and Texas.

Representatives of the genus are known for solitary, spherical or cylindrical, ribbed stems and a virtually complete absence of spines, although some species do have a few curved needles. The surface can be smooth or covered with white scales that form unusual, light-colored, felted, marbled patterns on the stem surface capable of absorbing moisture. Leaves are absent; the plant body is green, often with a glaucous bloom, decorated with areoles bearing spines.

The cacti grow very slowly, but they bloom early with large, funnel-shaped, yellow flowers, sometimes with a red center, located at the apex of the stem. The flowers usually wither after two or three days. With proper care, flowering lasts for an extended period, from spring to late autumn. Fleshy pubescent fruits with thin skin contain black or brown seeds.

Astrophytum myriostigma 'Columnare' has a stem ranging from grayish-green to white-gray. It is elongated, cylindrical, 25-50 cm (9.8-19.7 in) in height and up to 8 cm (3.1 in) in diameter. The ribs are sharp, wavy, with a V-shaped pattern. The flowers are yellow and silky-glossy.

Before sowing, seeds are soaked for 3-6 hours in warm water with the addition of stimulants (SUPERthrive, HB-101, Aminosol, Epin, or Zircon), after which they are disinfected for 10 minutes in a weak solution of potassium permanganate, then air-dried and sown on the surface of a moist substrate consisting of leaf mold, river sand, and finely crushed charcoal in a 1:1:1 ratio. They are moistened from a spray bottle, covered with film or placed in a propagator, and germinated in light, but not direct sun, at a temperature of 20-25 °C (68-77 °F), preferably with a reduction in night temperature to 15-18 °C (59-64 °F). Regular ventilation is carried out and uniform humidity is maintained.

Seedlings appear within 10-30 days, depending on temperature and humidity. The maximum germination period can exceed 45 days. Care must be taken with watering so as not to ruin the sprouts. Pricking out is carried out when 2-3 true tubercles appear, after which the plants are transplanted into individual containers. The seedlings, somewhat larger than those of other globular cacti at this time, develop slowly but steadily. Flowering occurs in the 4th-6th year if the dormancy regime and good lighting are observed.

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The plant is placed in a sunny location, preferably on a south or southwest window. Fresh air access and the absence of moisture stagnation are provided. In summer, the temperature is maintained at 22-30 °C (72-86 °F). In autumn, the plant is prepared for a dormant period, and by winter the temperature is gradually reduced to 10-12 °C (50-54 °F) with complete dormancy.

Watering is carried out moderately, after the substrate dries out, completely soaking the root ball with water. In the winter period, watering is eliminated. With the onset of the growing season, the ambient temperature is gradually raised above 12 °C (54 °F); at temperatures below this, the plant is unable to absorb water. The first watering is done carefully and with a small amount of water.

A stable and shallow pot with a mandatory drainage layer is selected for cultivation. A mineral substrate with the addition of sand, gravel, and crushed brick is used. Repotting is carried out in spring, carefully trying not to damage the root system, as new roots grow back with difficulty. Astrophytum is potted on into a container not much larger, so that it just fits inside. Repotting is done from dry soil into dry soil, and watering is carried out 5-7 days later so that damaged roots can dry out. Mature plants, starting from 10 years of age, are repotted rarely, with an interval of 5-6 years and only if roots encircle the entire soil ball.

During the growing season, plants are fed once every 4 weeks with specialized cactus fertilizers low in nitrogen, at a diluted concentration. Fertilizers are not applied during the dormant period. Plants tolerate elevated calcium content in the soil poorly. Shaping is not required. Propagation is carried out by seeds. Offsets are not formed.