The Argentine Giant Cactus, scientifically known as Echinopsis candicans (sometimes classified as Trichocereus candicans), is a popular and dramatic specimen among home gardeners. This cactus is celebrated for its impressive size and its tendency to form large, mounding clusters of ribbed columns. It is often sought after for its architectural presence in a xeriscape or desert garden, offering a bold, sculptural look. Its common name speaks directly to its South American origin and its potentially massive form.
Identification and Physical Characteristics
The Argentine Giant Cactus develops a distinctive growth habit, characterized by a clumping form where multiple stems branch from the base to create a dense mound. Individual stems are columnar, typically light green, and grow to a diameter of about 5 to 7 inches across, reaching a height of up to 24 inches but spreading much wider over time. The surface of the stem is lined with 9 to 11 obtuse ribs.
Along these ribs are large, white-felted areoles from which spines emerge. Each areole is densely packed with a grouping of sharp, yellowish to brownish-yellow spines. The spines are differentiated into radial spines, which spread outward and can be up to 1.6 inches long, and a few longer central spines that can measure up to 4 inches in length. As the plant matures, it forms a sprawling, low-growing cluster that can reach a spread of 3 to 10 feet.
Natural Habitat and Origin
The natural range of the Argentine Giant Cactus is concentrated in South America, specifically in Argentina. It is found across several provinces, including Mendoza, San Juan, Córdoba, and La Pampa, thriving in varied environments from sea level up to 6,560 feet in altitude. This native habitat includes the arid conditions of the Monte Desert, Chaco woodlands, and the foothills of the Andes.
The plant is conditioned to be drought-tolerant due to the dry climate and high temperatures of these regions. Its ability to endure a wide range of conditions includes a notable tolerance for cold snaps. It is cold-hardy, able to survive short periods of temperatures as low as 17°F.
Cultivation and Maintenance
Successful cultivation requires mimicking the well-drained, arid conditions of its native habitat. The plant requires a specialized soil mixture to prevent water retention and subsequent root rot, ideally a gritty or sandy soil incorporating components like perlite or coarse sand to ensure rapid drainage.
This cactus demands full sun exposure for optimal growth. It can tolerate light or partial afternoon shade, particularly in extremely hot climates where it may be susceptible to sun-scorching.
The watering schedule must align with the plant’s seasonal growth cycle to prevent overwatering. During the active growing season in spring and summer, the plant should be watered thoroughly, but only once the soil has completely dried out. A deep, infrequent watering technique is preferred, such as watering every 10 to 14 days during the hottest months.
Watering should be significantly reduced or stopped entirely during the winter months to allow the plant to enter a dormant period. During the growing season, a balanced, low-nitrogen fertilizer can be applied monthly to support robust growth, but feeding should cease in winter. For propagation, new plants are easily started from stem cuttings, which should be allowed to form a protective callous over the cut end before being placed in dry soil.
The Spectacular Night-Blooming Flowers
The most captivating feature of the Argentine Giant Cactus is its magnificent, short-lived flowers, which give it a reputation as one of the most fragrant cacti. These blooms are nocturnal, beginning to open near sundown and typically closing by mid-morning. This night-blooming habit is an adaptation to attract specific pollinators, such as moths and bats, which are active after dark.
The flowers are remarkably large and showy, appearing in late spring or early summer. They are funnel-shaped and can reach an impressive size of up to 8 inches across and 7.5 to 9 inches long. The petals are usually a bright, gleaming white, often with a yellow center, and the blooms possess an intense, sweet fragrance that perfumes the night air.
While a single flower often lasts only one night, the plant produces multiple flowers over a period of weeks. The blooms may also stay open longer on cool or cloudy days.