Pack Size: 20, 100, 300
Year: 2026
Accepted Scientific Name: Myrtillocactus geometrizans (Mart. ex Pfeiff.) Console
Common Name: Blue Myrtle Cactus, Blue Candle Cactus, Bilberry Cactus
Origin and Habitat:
Myrtillocactus geometrizans is a distinctive columnar cactus native to Mexico, particularly the central and southern regions, including Hidalgo, Querétaro, Guanajuato, Puebla, and Oaxaca. It inhabits arid and semi-arid valleys, rocky hillsides, dry tropical woodlands, and open shrublands, growing in mineral-rich, well-drained soils. These environments experience warm summers, mild to cool winters, and seasonal rainfall followed by extended dry periods. Plants frequently grow among rocky outcrops and sparse vegetation, where they receive abundant sunlight and experience considerable temperature fluctuations. In its natural habitat, the species develops into a large, branching, tree-like cactus, providing food and shelter for wildlife. Its edible fruits, known locally as garambullos, have traditionally been harvested and consumed in Mexico.
Description:
Myrtillocactus geometrizans is a moderately fast-growing, columnar cactus characterized by its distinctive blue-green to powdery blue stems and attractive branching growth habit. Mature plants can reach approximately 120–180" tall in their natural habitat, occasionally becoming larger, with a broad, tree-like crown. Container-grown specimens generally remain considerably smaller.
Individual stems typically measure 2.5–4" in diameter and develop 5–8 prominent, rounded ribs. The epidermis is covered with a powdery, waxy coating that produces its characteristic blue colouring. Each areole develops approximately 5–9 short radial spines, initially reddish-brown to dark brown and gradually fading to grey, occasionally accompanied by a longer central spine.
Young plants initially develop a single upright column before producing numerous lateral branches, eventually forming an attractive candelabra-like structure. Mature specimens produce clusters of small, funnel-shaped flowers approximately 0.8–1.2" across, displaying creamy white to pale greenish-white petals. Flowers emerge along the upper portions of mature stems during spring and early summer.
Following flowering, plants produce small, rounded, dark purple to nearly black edible fruits approximately 0.4–0.8" in diameter. These sweet, berry-like fruits are highly valued in Mexico. Its striking blue stems, architectural branching habit, and ornamental appearance make it an excellent addition to cactus collections.
Cultivation:
Zone: 9–11; protect from prolonged frost and excessive winter moisture.
Temperature: Optimal growth at 20–30 °C. Maintain winter temperatures above 8–10 °C for reliable cultivation.
Growth Rate: Moderate to fast under favourable conditions, initially producing an upright column before developing multiple lateral branches and a distinctive candelabra-like growth habit.
Soil: A fast-draining cactus mixture containing pumice, fine gravel, and a moderate proportion of organic matter. Excellent drainage and adequate root aeration are essential for healthy growth.
Watering: Water thoroughly during active growth, allowing the growing medium to dry between waterings. Established plants tolerate extended dry periods but benefit from regular watering during warm weather. Reduce watering significantly during autumn and keep mostly dry during winter dormancy.
Fertilizing: Apply a diluted, low-nitrogen cactus fertilizer every 2–3 weeks during active growth. Discontinue feeding during winter.
Light: Full sun to bright, filtered sunlight. Strong light encourages compact growth, healthy branching, and intense blue stem colouring. Provide protection from intense afternoon sunlight during extreme heat, particularly for young plants.
Pests and Diseases: Susceptible to mealybugs, root mealybugs, scale insects, spider mites, and root rot associated with excessive moisture or poorly draining growing media.
Germination Info:
Temperature: 27 °C.
Surface Sown: Yes. Sow seeds on the surface of a fine, sterilized cactus growing medium and press lightly into place. A very thin covering of fine mineral material may be used.
Germination Time: Approximately 7–21 days under favourable conditions, although some seeds may require longer.
Moisture: Maintain consistent surface moisture and high humidity during germination, avoiding waterlogged conditions.
Light: Bright, indirect light. Avoid direct sunlight on covered seed trays.
After Germination: Gradually increase ventilation as seedlings establish. Maintain moderate moisture until young plants develop stronger root systems. Introduce brighter light gradually as seedlings mature and begin developing their characteristic blue-green stems and spines.
