Agave asperrima
Agave asperrima used to be called Agave scabra. The name is sometimes used synonymously.
Agave asperrima species, subspecies, varieties and forms
Agave asperrima species, subspecies, varieties and forms
By Michiel1972 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=18081790
Agave asperrima
Hardy to around 15°
Agave asperrima (Sierra Del Carmen, MX Big Bend Form sold by Ethical Desert)
Hardy to -11° possibly lower, but may take damage
Agave asperrima ssp. maderensis 'Grand Duke'
Hardy to 10°
Agave asperrima spp. potosiensis, Potosi Agave
Hardy to 5-10° (the variegated form is only hardy to 15°)
Agave asperrima ssp. zarcensis, Zarca Agace
Hardy to 15°