Acanthocalycium GLAUCUM

Acanthocalycium GLAUCUM - Glaucous acanthocalycium, Acanthocalycium glaucum.

Acanthocalycium is a genus of plants in the cactus family (Cactaceae) from northern Argentina, comprising about 12 species. In their natural habitat, the plants inhabit mountain meadows at elevations up to 1,000 m (3,280 ft) above sea level.

Plants are solitary, spherical or slightly cylindrical, up to 60 cm (23.6 in) tall and up to 15 cm (5.9 in) in diameter, with 9-20 slightly wavy ribs. The stem is colored in green, dark blue, gray, or powdery glaucous tones. Areoles are located at the tops of the tubercles and contain 5-10 radial and 1-4 central stiff, resilient spines up to 3 cm (1.2 in) long, colored gray, yellow, reddish, or black.

Flowers appear from May to September, funnel-shaped, up to 5 cm (2.0 in) in diameter, gathered in a lush crown. The petals range from white to soft violet, and the perianth is lemon-yellow. The fruits are dark green, spherical, up to 2 cm (0.8 in) in diameter, containing large dark seeds.

Acanthocalycium glaucum has a cylindrical stem, bluish-green, up to 15 cm (5.9 in) tall, and up to 7 cm (2.8 in) in diameter. Ribs, numbering from 8 to 14, are softly defined and high. The areoles are sparsely spaced and white. Radial spines number from 5 to 10, straight, stiff, from 5 mm (0.2 in) to 2 cm (0.8 in) long, colored from dark gray to black. Central spines are absent, but in rare exceptions 1-2 appear on young areoles.

Flowers are golden yellow, 6 cm (2.4 in) in length and diameter, with the floral tube covered in bristles. Fruits are spherical, dark green, 2 cm (0.8 in) in diameter. Seeds are dark brown and large.

A fungicide solution at the recommended concentration is poured into the tray. After moistening the substrate, seeds are sown on the surface, moistened with a spray bottle, and covered with film. Germination is carried out in light (not direct sun) at a temperature of 20-22 °C (68-72 °F) with regular ventilation. Over-drying and waterlogging are not allowed.

Seedlings appear in 7-14 days. The maximum possible germination period is up to 30 days. After 6 months or upon the appearance of the first spines, seedlings are repotted into individual 5 cm (2.0 in) pots or into seedling trays at a distance of 1 cm (0.4 in) apart. Young plants develop steadily and evenly.

© Greeniverse. All rights reserved.

Acanthocalycium is placed in a well-lit location, preferably on a south or south-west window. With a lack of light, the stem stretches and the spines become weak. In summer, it is recommended to take it out into the fresh air. In greenhouses, shading is not required.

Temperature in summer is maintained within 20-38 °C (68-100 °F) with good ventilation. In winter, a temperature of 6-10 °C (43-50 °F) is preferred, with a minimum of 4 °C (39 °F). Watering in summer is done approximately once every 2 weeks, or slightly more often when using small pots. In winter, watering is omitted, but overhead spraying once every 2 months is permissible.

A substrate composed of 2 parts clayey or depleted soil and 1 part coarse sand is used. Repotting is performed in spring. Up to a pot diameter of 13 cm (5.1 in), it is repotted annually, then as needed (once every 8-10 years). Fertilizers are applied once a month in spring and summer, using fertilizers with a higher potassium content. Full flowering requires bright sun. The plant usually begins blooming at the age of 4 years, upon reaching 7-8 cm (2.8-3.1 in) in diameter.