Synonyms:

No officially recognized synonyms.

Habitat:

This form is a nursery-produced cultivar, selected and maintained exclusively in cultivation. The botanical species it derives from, Myrtillocactus geometrizans, is native to north-central Mexico, with a natural range extending down to the state of Oaxaca, where it grows in arid and sunny environments with rocky, well-draining soils.

Description:

The genus name Myrtillocactus literally means “cactus with blueberry-like fruits”, referring to the small, dark and spherical berries produced by the species. Geometrizans alludes to the regular, almost “geometric” shape of the stems. The term cristata describes the fan-shaped and undulating growth typical of this mutation, which replaces the plant’s natural cylindrical form with wavy, sinuous lines.

Myrtillocactus geometrizans f. cristata belongs to the genus Myrtillocactus and to the family Cactaceae. It displays a distinctive “ruffled fan” growth pattern that replaces the species’ usual cylindrical stems. The crest appears as a continuous, undulating surface of varying width, marked by irregular ribs that follow the serpentine movement of the plant. Its edges can be softly curved or more sharply defined, creating intricate natural patterns. The epidermis retains the species’ characteristic blue-green tones, dotted with small pale areoles that produce short and sparse spines.

Flowering in the crested form tends to be modest, occurring mainly along the most stable portions of the crest. The flowers are small and pale, white with a hint of green, and open briefly from spring to summer, offering a delicate contrast against the bluish-green epidermis. When conditions are favorable, they are followed by the species’ typical round, dark berries that resemble blueberries. In this form, however, fruit production is usually sporadic and appears more commonly on mature plants.

Cultivation:

This is a generally easy plant to grow, with a fairly rapid growth rate.

The soil for Myrtillocactus geometrizans f. cristata must be very well-draining, light and rich in mineral components to prevent any water stagnation. An airy mix based on inert materials such as pumice, lava rock or fine gravel is ideal for keeping the roots dry and well oxygenated. The plant performs best in a pot with drainage holes, which allows water to flow out quickly and reduces the risk of rot.

During the warm season, this cactus appreciates regular watering which, under full sun and mild temperatures, can be done about once a week. The substrate should always be allowed to dry out completely between waterings to prevent excess moisture that could damage the crest. With the arrival of fall, watering should be gradually reduced and almost completely suspended during winter.

This plant grows best in very bright conditions, preferably with direct sun for most of the day. Young specimens or those recently repotted may benefit from slightly filtered light during the hottest hours to avoid sunburn; well-acclimated plants, however, handle full sun exposure without issues. Indoors, it’s important to place it in the brightest spot, as insufficient light can cause crest deformities. The plant does not tolerate temperatures below 50°F (10°C), so during the cold season it should be adequately protected or moved to a sheltered location.

Fertilizing Myrtillocactus geometrizans f. cristata should be done in moderation, using a cactus-specific fertilizer that is low in nitrogen and high in potassium. During the growing season, a light feeding every 4-6 weeks supports growth without altering the compact shape of the crest. In winter, fertilization should be completely suspended.

Periodic repotting helps this plant maintain a healthy, well-developed root system. Typically, repotting every 2-3 years is sufficient, choosing a slightly larger pot always equipped with drainage holes to prevent water retention. The operation should be carried out in spring, when the plant resumes active growth, using a very well-draining substrate and being careful not to damage the edges of the crest.

This plant is not considered toxic to humans or pets. However, its spines, though short, may cause mild skin irritation. It is therefore advisable to handle it with care, especially during repotting and cleaning.

Issues related to diseases and pests are relatively uncommon but may arise under suboptimal growing conditions. Excess moisture is the main risk factor, as it can lead to rot at the base of the crest or within the areoles. In poorly ventilated environments, mealybugs may appear, particularly in the folds of the crest where they find shelter and are harder to notice. Mites can also show up occasionally, leaving small discolored spots on the stem’s surface.

A useful precaution is to avoid direct contact with the plant’s epidermis: its waxy surface can retain the thin oily film from the skin, leaving visible marks that are difficult to remove.

Propagation:

Propagation is carried out almost exclusively through cuttings, as the mutation does not remain stable when grown from seed. Sections of the crest are taken with clean cuts, allowed to dry for a few days until a callus forms, and then placed on a very well-draining substrate, kept only slightly moist during the initial stages.

Curiosity:

This plant is also known as the “Dinosaur Back Plant”, a name inspired by the appearance of its crest: the irregular waves and pronounced ribs resemble the profile of a dinosaur’s back, with raised sections that look like sequential plates or vertebrae.

Official Web Site:
www.giromagi.com

Italian Blog:
www.giromagicactus.com

Tips:
Read our advice