Dasylirion is a genus of 17 species of grassy looking rosette plants in the family Ruscaceae, all native to northern Mexico, with three species also extending into the south-western United States. They are not grasses but are related to the Agaves. As they grow older, the bases of several species develop into a beautiful trunk. When the plants are mature they send out blooms with hundreds of greenish-white bell-shaped flowers on a tall narrow spike coming from the center of the plant. Unlike most Agaves they do not die after blooming. Most Dasylirion species are reasonably resistant to cold and drought.

Dasylirion longissimum commonly known as the Mexican Grass Tree is a large plant native to North-eastern Mexico with glaucous-green stiff unarmed grass-like 1.8m long leaves. The leaves radiate symmetrically out of a large woody trunk that can slowly but eventually grow 1.8 to 4.5m tall. In summer, a nine foot tall spike of small white flowers emerge from reddish buds. Plant it in full sun to light shade. It is drought tolerant and cold hardy to at least -12°C and makes a great container plant or focal point specimen in the garden. The older, bottom leaves can be trimmed off to expose the trunk.