Agave ferdinandi-regis A.Berger 

🌱 Morphology
   A very slow-growing agave that develops a compact, practically stemless rosette, approximately 35–45 cm tall and 40–60 cm in diameter. The leaves are rigid, thick, triangular, and slightly concave on their upper surface, with an upward arrangement and a dark green to bluish-green color. Its most spectacular feature is the white leaf-impression marks (bud prints), which draw converging lines on the surface of the leaves and form highly beautiful geometric patterns. The margins are smooth, without teeth, and show a reddish-brown corium tone. Each leaf ends in a robust dark terminal spine, sometimes accompanied by small secondary spines. It is generally a solitary plant, although it may occasionally produce basal offsets.

🌍 Distribution, habitat, and family
It is native to northeastern Mexico, especially the mountainous regions of Coahuila and Nuevo León, in the area of the Sierra Madre Oriental. It grows on rocky slopes, limestone outcrops, and stony soils in semi-arid environments, where high sunlight and natural soil drainage limit water availability.

It belongs to the family Asparagaceae, subfamily Agavoideae. There is some taxonomic discrepancy regarding its identity: Agave ferdinandi-regis A.Berger is considered a synonym of Agave nickelsiae in Plants of the World Online (Kew), while other classifications include it within Agave victoriae-reginae. The original name continues to be widely used in horticulture and collecting.

❄️ Temperature · USDA Zone 8b
Tolerates minimum temperatures of up to −8 ºC when dry and with well-acclimatized adult specimens. It is especially sensitive to the combination of cold and persistent moisture on the roots. During frosts, it is advisable to keep the substrate completely dry.

☀️ Lighting
Requires full sun or very intense lighting to develop a compact rosette and maintain the contrast of its characteristic white marks. As a target during active growth, a DLI PAR of 20–30 mol·m⁻²·day⁻¹ is recommended. In environments with extreme summer solar radiation, it may benefit from light protection during the middle hours of the day.

💧 Growth cycle and watering
Winter dormancy. During winter, it is recommended to considerably reduce watering and keep the substrate practically dry when temperatures are low. In spring and summer, during active growth, it is recommended to water deeply and let the substrate dry out completely before watering again. It is a very drought-resistant species, but especially sensitive to waterlogging and prolonged moisture on the roots.

🌸 Flowering
Flowering appears after several decades of growth, generally when the plant has reached maturity. It develops a spectacular erect inflorescence approximately 2–4 m tall, with numerous flowers clustered along the floral axis. The flowers show yellowish, greenish, and reddish tones. Like other monocarpic agaves, the rosette that flowers dies after producing seeds, although it may occasionally have produced offsets before flowering.

🌿 Nutrition
During active growth, Desert CHOICE® Succulents is recommended, formulated with a high content of assimilable potassium and calcium. For Agave, the use of Desert CHOICE® Flowering is not recommended.

This is an inimitable xerophyte cultivated in Madrid in a technological square pot and with the substrate activated with mycorrhizal fungi and biofungicides.