Pilosocereus PACHYCLADUS

Pilosocereus PACHYCLADUS - Blue Columnar Cactus, Blue Torch Cactus, Pilosocereus azureus, Pilosocereus AZUREUS.

Pilosocereus is a genus of columnar succulent plants in the Cactus family (Cactaceae), comprising about 61 accepted species distributed from Florida, the Caribbean region, Mexico, and Central America to tropical South America. In nature, members of the genus occur in dry tropical forests, xerophytic shrublands, on rocky slopes, sandy areas, in semi-desert regions, and other places with bright sun, good drainage, and distinct dry periods.

Plants usually develop as shrubby, tree-like, or columnar cacti with erect, ascending, or branching stems. Many species are distinguished by bluish, glaucous, or waxy shoot coloration, distinct ribs, large areoles, spines, and zones of dense woolly pubescence, especially in the area of future flowering.

Flowers in Pilosocereus are usually tubular or funnelform-tubular, often nocturnal or crepuscular, with greenish, pinkish, reddish, or whitish hues. After pollination, fleshy fruits develop with juicy pulp and numerous small dark seeds. When sowing, seeds are distributed on the surface or near the surface and require stable warmth, light, and careful moistening.

Blue columnar cactus is a columnar cactus up to 10 m (33 ft) tall, light blue when young, branching with 6 straight ribs. Dense, long down forms in the apical areoles. Flowers appear from them. The flowers are pink, 4-7 cm (1.6-2.8 in) long and 2.2-4.5 cm (0.9-1.8 in) in diameter. They appear only under favorable conditions and upon reaching a certain age. They flower better when kept in greenhouses. Spines are straw-colored. Central spines numbering 1-12, up to 3 cm (1.2 in) long; radial spines numbering 8-18, 0.5-1.5 cm (0.2-0.6 in) long.

Pilosocereus seeds are small, black, rounded or slightly oval. Seed germination under careful greenhouse conditions is usually about 50-80%.

Sowing is conducted in spring or, with stable lighting, year-round. A sterile fine-grained mineral substrate based on sifted cactus soil, fine sand, perlite, and mineral grit is used. Seeds are distributed on the surface, lightly pressed into moist soil, and dusted with a minimal layer of fine sand or not covered at all. Sowing is moistened from a spray bottle with a weak solution of potassium permanganate or biofungicide with the addition of a growth stimulant: SUPERthrive, HB-101, Aminozol, Epin, or Zircon. The container is covered with a transparent lid or placed in a propagator.

Germination is conducted under bright diffuse lighting and a temperature of about 24-28 °C (75-82 °F), without direct overheating under the sun. The surface is kept moderately moist but not wet; moistening is performed only by fine spraying. Sowings are ventilated daily, condensation is removed, as stagnant moisture is dangerous for Pilosocereus seedlings and quickly causes fungal damage.

First shoots may appear in 7-10 days; the usual germination period is 10-21 days; the maximum possible period under temperature fluctuations or partial surface drying can extend to 4-6 weeks. After emergence, the cover is gradually opened, and seedlings are kept in bright diffuse light and careful moistening. Pricking out is carried out after noticeable strengthening of plants and appearance of the first spines, usually no earlier than several months, with minimal damage to roots.

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For growing, the brightest possible location with direct sun for at least 4-6 hours a day is chosen. South, southeast, and southwest windows, bright balconies, and well-ventilated terraces are best suited. With a lack of light, stems stretch out, coloration becomes less glaucous, pubescence develops more weakly, and the plant tolerates watering worse.

During active growth, a temperature of about 22-30 °C (72-86 °F) is maintained with good air circulation. The plant is warmth-loving, so prolonged cold conditions are undesirable. Overwintering is conducted in bright, dry, and moderately warm conditions, around 12-15 °C (54-59 °F), with very careful watering. A short-term drop in temperature is possible only with completely dry substrate and good ventilation.

Watering is carried out moderately, after complete or almost complete drying out of the substrate. In spring and summer, the soil is moistened in small portions, with mandatory draining of water from the saucer. In autumn, watering is gradually reduced; in winter, the plant is kept significantly drier. Water getting on dense pubescence is undesirable, as moisture can linger between hairs and cause spots or localized tissue damage.

A very loose, well-drained cactus substrate is used with the addition of coarse sand, pumice, zeolite, fine stone grit, perlite, or other inert aerators. The organic fraction is added moderately. Generous drainage is placed at the bottom of the pot, and the container is chosen to be stable, sufficiently deep for a vertical plant, and strictly with drainage holes.

Fertilizer is applied only during active growth, once every 4-6 weeks with a weak solution of cactus and succulent fertilizer with reduced nitrogen content. Excess nutrients cause loose watery growth and reduce resistance to rot. Repotting is carried out in spring, approximately once every 2 years or as the pot fills with roots; after repotting, the plant is kept without watering for several days. Pruning is usually not required, and damaged parts are removed only with clean tools.