Agave х nigra hort.
Agave nigra is probably a natural hybrid found in Mexico, Sonora; now, it is common only cultivated.
The characteristical shape of this Agave makes it really recognizable. The rosette is small but robust, acaulescent, openly spreading. It gets a 50-60 cm diameter, but rarely get taller than one meter. Leaves are thick (particularly toward the base) and rigid, stiff, lanceolate or triangular and the rough and leathery texture make it earn the “Sharkskin Agave” common name. Their colour is a very deep grey-blue, but purple black is present on the terminal spine and on their smooth margins. This plant blooms after decades of life in summer, then it dies. The sterile flowers are yellowish, and the stem can get tall up to 4 meters.
This Agave is a fast growing. It is a frost-resistance plant: it can tolerate down to about -8°, -12° C if dry. To grow at its best, it needs a large pot. It can also be planted in groups, and in in rock garden. It requires a well drained soil. To make growth faster, use organic fertilizer and watering.
Propagation can be done by suckers that are developed mostly by young plants.
This Agave presents a typical architectural shape, which is so special that it can be hardly confused with any other Agave.