Scattered along the stiff, upright stem of this unusual perennial are tough, blue-green, yucca-like, parallel-veined leaves. Smooth, rigid stems bear thistle-like flower heads made up of small greenish-white florets mingled with pointed bracts. The individual, greenish-white flowers cluster into unique, globular heads. These occur on branch ends atop the 6 ft. plant.
Their spiny leaves make walking through clumps of these plants difficult, and also make them unpalatable to grazing livestock. They were once credited with a variety of curative powers. Their flower heads develop a bluish cast with maturity.