Yucca rigida:

Yucca rigida is in general a single trunked species, but occasionally it forms multiple trunks growing up to 4-5 m height.
The beautiful light blue stiff leaves are 30-70 cm long and are 1,2 to 2 cm wide, but in cultivation they can reach 120 cm in length, ending in a stiff dark brown spine.
The leaves are also lined with a yellow margin and very tiny teeth.
The inflorescence is a panicle of 60 cm and hidden partially by the leaves, the flowers are like most species creamy white and 4-6 cm long.
Y.rigida is only found in northern Mexico were it grows on rocky hill sides.