Synonyms:

Cereus schottii
Pachycereus schottii
Lophocereus gatesii
Myrtillocactus schottii

Habitat:

Lophocereus schottii grows naturally in the arid and semi-arid regions of Baja California, Sonora, and southern Arizona, within the Sonoran Desert. It is typically found on rocky slopes, gravelly plains, and dry riverbeds, where the soil is sandy or stony and drainage is excellent. Its elevation range generally extends from sea level up to about 1,000 meters.

Description:

The name of the genus Lophocereus derives from the Greek lophos, meaning “crest” or “tuft”, and the Latin cereus, a term used to describe columnar cacti. It refers to the woolly or crested apical parts that some species in this genus may develop. The specific epithet schottii honors Arthur Carl Victor Schott (1814–1875), a naturalist and botanist who collected specimens of this plant during his explorations in the southwestern United States and northern Mexico.

Lophocereus schottii is an upright, columnar cactus that tends to branch from the base, producing numerous erect stems. Under optimal conditions, it can reach 5–7 meters (up to 6 meters) in height and 10–15 centimeters in diameter. However, in southern California, where occasional frosts may occur in lowland areas, it remains more compact. The stems, glaucous green to grayish in color, have 6–8 distinct, rounded ribs coated with a thin waxy bloom. The areoles, arranged at regular intervals along the ribs, are covered with whitish wool and bear sharp spines—in mature plants, up to 20 at the apex, reaching about 10 cm in length and gray in color. On older stems, the spines tend to shorten or disappear. Mature specimens may develop the characteristic monstrous or “totem” form, resulting from abnormal growth that produces knobby, irregular stems.

It blooms from late spring to summer, occasionally extending into early autumn in warmer regions of its range. The tubular flowers, about 5-8 cm long, emerge from the upper parts of the stems and open only at night for a few hours. Their petals are pale pink inside and greenish white outside, and emit an unpleasant odor that attracts senita moths (Upiga virescens), the species’ primary pollinators.

The fruits are round, red, and spineless, with a sweet pulp and numerous glossy black seeds.

Cultivation:

This species is generally easy to cultivate, provided that its typical desert cactus requirements are met.

It prefers a mineral, highly draining substrate with a low percentage of organic matter. An ideal mix for cacti consists of sandy soil, pumice, and coarse gravel, which ensures good aeration around the roots and prevents water stagnation.

It requires moderate, well-spaced watering, only when the substrate is completely dry. During the growing season, in spring and summer, watering can be carried out regularly, but all standing water must be avoided. In autumn, watering should be gradually reduced and suspended entirely in winter, when the plant enters dormancy.

It needs full sunlight and many hours of direct exposure to develop a compact form and maintain its characteristic gray-green stem coloration. It tolerates intense heat and drought well but is sensitive to prolonged cold and frost, especially in humid conditions. In areas with harsh winters, with temperatures below 42 °F, it should be placed in a sheltered or bright greenhouse, ensuring good air circulation.

This cactus does not require frequent feeding; a light fertilization every 4-6 weeks during the growing season is sufficient, using a low-nitrogen fertilizer formulated for cacti. Fertilization should be stopped during autumn and winter.

Repot every 2-3 years, preferably in early spring, when growth resumes. The purpose is to renew the substrate and provide additional space for the roots, which tend to grow deep. Use a pot just slightly larger than the previous one, with excellent drainage and a layer of coarse material at the bottom.

Lophocereus schottii poses no particular toxicity risks to humans or pets. As with all cacti, it is advisable to handle it carefully to avoid minor injuries from the sharp spines.

It is a hardy species, but excessive humidity or poor drainage can lead to root or collar rot, often caused by fungi such as Fusarium or Phytophthora. Affected parts should be removed, and the plant repotted in a dry, well-draining substrate.

The most common pests include mealybugs and scale insects, which nest in the areoles and along the stems, and occasionally mites or red spider mites in overly dry environments. Good air circulation and proper watering are the best preventive measures.

To keep Lophocereus schottii in excellent health, it is essential never to overwater. This species tolerates drought well but can suffer from even brief periods of water stagnation.

Propagation:

It propagates easily through stem cuttings, a method that ensures plants identical to the parent specimen. Cuttings should be taken in spring or summer and left to dry for a few days in a shaded place until the cut surface is completely calloused. They can then be placed in a sandy and slightly moist substrate, kept at a temperature of around 20 °C (68 °F) until rooting occurs. To increase the chances of success, several cuttings can be prepared at the same time.
Seed propagation is also possible, though slower: the seeds should be sown in a sandy loam soil, kept at a high level of humidity and a temperature of about 14 °C (57 °F) until germination.

Curiosity:

In the desert regions of Mexico and Arizona, Lophocereus schottii is commonly known as the “Senita cactus”, a name derived from the Spanish senita, meaning “little old man”. The term refers to the tufts of whitish wool covering the areoles of mature stems, reminiscent of gray hair, which gives the plant its distinctive “aged” appearance.

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