Agave shrevei subsp. magna

Agave shrevei subsp. magna belongs to a species of the Sierra Madre Occidental in north-western Mexico and grows where the states of Chihuahua, Sonora and Sinaloa meet. According to a California succulent garden, it is the largest of the three subspecies of A. shrevei and forms handsome rosettes of blue-grey leaves. Its tall inflorescence has branches held at right angles, with greenish flowers held upright at their tips, purple filaments and pale yellow pollen jutting from the floral tube. The English Wikipedia says two subspecies of A. shrevei are recognised and magna has been proposed as a third, while GBIF treats magna as an accepted subspecies. A. shrevei propagates mainly by seed and grows slowly compared with larger agaves. Locally the young flower stalks are eaten raw or made into drinks, and the leaf bases are roasted and eaten. Specific size and hardiness data are scarce, and it is distinguished from subspecies such as matapensis by its larger size. In Japan specialist nurseries sell seedlings and seed.

Source: Wikipedia (CC BY-SA 4.0)

Light feeder; a little slow-release fertiliser in the growing season is enough