Obregonia DENEGRII

Obregonia DENEGRII - Obregonia De Negri, Obregonia denegrii, Artichoke Cactus.

Obregonia is a monotypic genus of plants in the cactus family (Cactaceae), growing exclusively in a small area in the Mexican Jaumave Valley and considered endangered.

The range of the sole species is limited to the state of Tamaulipas in northern Mexico. Across an area of 350 km² (135 sq mi), there are five separate populations with a total number of fewer than 5,000 specimens. The plants grow on open, heavily weathered clay or limestone slopes, most often in the shade of bushes.

The plant has a spherical or slightly elongated stem, up to 20 cm (7.9 in) in diameter, covered with large (1.5 cm (0.6 in) long, 2.5 cm (1.0 in) wide), broad, leaf-like, acute, thick, trihedral tubercles. In the axils of these tubercles, abundant white wool forms. Flowers develop in young areoles. Thin, light yellow spines quickly fall off. Old areoles are completely bare.

From May to September, funnel-shaped white flowers are formed, reaching a diameter of up to 3 cm (1.2 in). The flowers have a bare floral tube. The fruits are fleshy. The seeds are black.

Obregonia De Negri is a solitary plant of a strongly flattened shape with a tuft of down and spines in the center, about 16 cm (6.3 in) in diameter, green in color. The tubercles are arranged in a spiral. The areoles have 3 to 6 small, soft, thin spines. In mature plants, spines are present only on the younger central tubercles. The root is a taproot. The flowers are white, located around the apex, up to 2.5 cm (1.0 in) in diameter. The petals are narrow. Flowering occurs in summer. The fruits are white with the dried flower attached, situated in the wool, and fragile when mature. The seeds are black, up to 1.5 mm (0.06 in) in diameter.

Seeds are sown on the surface of a moist sandy substrate, moistened with a spray bottle, covered with film, and germinated in the light, but not in direct sun, at a temperature of 24-26 °C (75-79 °F). Seedlings need ventilation. It is necessary to avoid waterlogging and drying out of the sowings.

After a few weeks, young sprouts appear on the surface of the substrate and are kept under the same conditions for a few more weeks. Once they grow stronger, the sprouts are carefully transferred with their soil into a new container for permanent growth. Care for young obregonias is the same as for adult plants, maintaining a stable temperature regime and protecting from direct sunlight.

Seedlings grow slowly. From 4 years of age, the growth rate increases significantly, and by 7-8 years the plant begins to bloom. Grafting is used to accelerate growth. Tubercle grafting is practiced.

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Obregonia feels best in greenhouse conditions, in a winter garden, or in a specially designated room for succulents. However, the plant can also be grown indoors. It is important to ensure that the woolly pubescence is protected from moisture and dirt, in order to avoid loss of the cactus's healthy appearance.

The plant likes well-lit rooms, but direct sunlight on overly hot days can be detrimental to it, while plenty of diffused light is just right. It is recommended to place it on south-eastern windows of the house.

Temperature readings can be around 22-26 °C (72-79 °F). Obregonia can equally well tolerate both heat and lower temperatures; it is desirable that changes occur gradually. Maintaining the temperature regime is important during the dormancy period from October to March, when the plant is placed in conditions with a temperature of 5-10 °C (41-50 °F). A dormant period is necessary for flowering. It withstands short-term frosts, provided that air and soil humidity are low.

The plant is watered with caution, abundantly, but rarely. For watering, soft, settled water at room temperature is used. During the dormant period, watering is stopped. Air humidity can vary within 35-55%. On excessively hot days, spraying the air around the plant is carried out using a fine mist spray bottle. Moistening the plant itself is not advisable, as this can lead to rot.

Slightly acidic soil is preferred, meeting conditions of lightness, low fertility, and good permeability to air and water. Obregonia is repotted as needed in early spring. For this, a mixture is prepared from: peat soil (2 parts), sand (2 parts), expanded clay (1 part), perlite (0.5 parts). Expanded clay and perlite are used as drainage components. With their help, a substrate is prepared in which the root system develops as quickly as possible. Also, a medium-small pot is chosen for the plant, slightly larger than the size of the plant itself.

Obregonia is fed as needed using organic liquid fertilizers for succulents and cacti. Fertilizers are applied along with watering in a weak concentration no more than once a month. During the dormant period, fertilizers are not applied.