Yucca potosina

Yucca potosina, English common name Potosí palm soapwort or Potosi palm, is native to the east central Mexico from Hidalgo to San Luis Potosi.
It is sometimes cultivated as an ornamental, but not widely.
Yucca potosina is a rather large treelike species up to 8 m tall, with occasional branching.
Leaves are gorgeous blue-green or yellowish green, stiff, narrow, rough, up to 100 cm long.
Inflorescence is up to 120 cm long.
Flowers are white, elongated, up to 50 mm long and 15 mm across.
Hardy to both drought and frost.