Synonyms:

Echinopsis spachiana f. supermostruosa

Habitat:

This form does not occur in the wild but originates from a monstrous mutation selected and maintained in cultivation. The type species, Trichocereus spachianus, is native to western Argentina and Bolivia, where it grows in arid and semi-arid environments, on rocky slopes and well-drained soils, generally at elevations between 1,000 and 2,000 meters.

Description:

The name Trichocereus derives from the Greek thrix (“hair”) and kēreus (“waxy”), referring to the presence of fine or bristle-like spines on stems with a waxy appearance. The specific epithet spachianus was assigned in 1839 by the French botanist Charles Antoine Lemaire in honor of his compatriot, the botanist Édouard Spach. The designation supermostruosa refers to a particularly pronounced monstrous growth habit.

Trichocereus spachianus f. supermostruosa belongs to the genus Trichocereus and to the family Cactaceae. It exhibits a highly irregular growth pattern, departing from the typical columnar form of the type species. The stem, normally upright and well defined, appears deformed, wavy, and sometimes twisted. It can reach heights of up to approximately 1.5 meters and generally has a diameter of 5-10 cm. In this form, the well-defined ribs typical of the standard form are replaced by irregularly spaced tuberculate crests. Stem coloration ranges from bright green to more subdued gray-green tones, depending on the plant’s age and light exposure. The areoles, irregularly distributed along the crests, produce short, sturdy spines, usually up to 1 cm long, sometimes reduced or nearly absent.

In this monstrous form, flowering may be more irregular or less frequent. When it occurs, it takes place from late spring to early summer and produces white, funnel-shaped flowers that open at dusk and generally remain open until the morning, emitting a delicate fragrance that attracts nocturnal pollinators such as moths. Each flower can reach 15-20 cm in diameter and is supported by a long floral tube covered with hairs and scales. After pollination, the plant produces fleshy, oblong fruits containing numerous small black seeds.

Cultivation:

It is an easy-to-grow plant, characterized by moderately fast growth.

The soil must be well draining to prevent root rot. Light substrates enriched with inert materials such as coarse sand, perlite, gravel, or pumice are recommended, as they promote rapid water drainage.

During the growing season, from spring to early fall, watering should be thorough but infrequent, allowing the soil to dry out completely between waterings. It is important that the pot has drainage holes to allow excess water to escape. In winter, watering should be greatly reduced, limited to occasional applications sufficient to prevent excessive tissue shriveling.

This plant prefers very bright conditions and grows best in full sun, with at least 6 hours of direct sunlight per day. It tolerates direct sun well if gradually acclimated. In areas with particularly hot summers, light afternoon shade may be beneficial to prevent sunburn. During the growing season, ideal temperatures range between 20 and 30 °C. The species shows good cold tolerance and can withstand brief frosts down to approximately -5 °C, but protection from prolonged freezing is recommended, especially for plants grown in containers.

During the growing season, light fertilization can be applied every 4-6 weeks using a balanced, water-soluble fertilizer diluted to an appropriate strength. Fertilization should be suspended during the winter months.

Repotting is infrequent and generally required every 2-3 years, or when the root system has fully filled the container. Spring is the preferred time for repotting, using a slightly larger pot and a well-draining substrate.

This plant is not considered toxic to humans or pets. However, as with many cacti, it should be handled with care due to the presence of spines, which may cause minor injuries or skin irritation.

Generally a hardy plant, it may occasionally be affected by common pests such as mealybugs and mites. Regular inspection allows for early intervention with treatments based on insecticidal soap or neem oil. Good air circulation, along with proper drainage and balanced watering, also helps prevent fungal diseases and root or collar rot.

Care tip: rotate the pot periodically to promote more balanced growth and reduce excessive stress or bending of the stem caused by the monstrous growth habit.

Propagation:

This plant is mainly propagated by cuttings. Stem segments should be left to dry for several days, allowing the cut surface to fully callus before being placed in a well-draining substrate. It can also be propagated by grafting, which helps preserve its distinctive features while benefiting from the greater vigor and resistance of the selected rootstock. Propagation from seed is possible only for the type species, as it does not ensure the transmission of the monstrous growth characteristics.

Curiosity:

The supermostruosa form of Trichocereus spachianus has become increasingly popular and widespread in Europe in recent years, while it appears to be rarer or less common in other regions, such as the United States.

Official Web Site:
www.giromagi.com

Italian Blog:
www.giromagicactus.com

Tips:
Read our advice