Scientific: Dasylirion quadrangulatum (formerly D. longissimum)
Common: Mexican grass tree, toothless sotol, longleaf sotol
Family: Asparagaceae (subfamily Nolinoideae)
Origin: Mexico in and around Coahuila, Tamaulipas, San Luis Potosi

Pronounciation: Da-sa-LIR-ee-on quad-ran-gu-LA-tum

Hardiness zones
USDA 7-10 (arid regions only)

Landscape Use: Specimen, textural accent, barrier, container plant for patios, xeric, oasis, or even mesic landscape design motifs

Form & Character: Large, evergreen shrub, calescent, agave like, rosetting and rounded, refined.

Growth Habit: Slow, non-clumping, trunk to 10 to 12 feet in height with 6 feet spread. Flower spikes will extend to heights of 15 to 20 feet.

Foliage/texture: Foliage densely rosetting to clumping, long, very narrow (almost linear), dull to dark green to 3 feet long, leaves with unarmed simple margins; fine texture.

Flowers & fruits: Dioecious, cream-colored flowers, plume-like, on a 10 to 15 feet stalk, plants will only flower after 7 to 10 years, and then will not flower every year thereafter.

Seasonal color: Flowers stalks in later spring to summer.

Temperature: Tolerant of some heat stress above 110oF and is slightly more cold tolerant than D. wheeleri.

Light: Full sun

Soil: Well drained

Watering: Somewhat drought tolerant, some watering during the summer is needed if toothless sotol is planted in the lower desert urban landscapes, otherwise none. It's best to irrigate sparingly if at all during the winter. In the lower desert, sotol will typically show significant leaf marginal tip necrosis.

Pruning: Only minimal pruning is generally needed. Minimal in this case means removing older dieing or dead leaves. If older dieing leaves are not removed then Mexican grass tree with develop a nice grass skirt. Sadly, in many cases, the improper planting of Mexican grass tree into small landscaped areas (spaces that are too small) will be the guiding motivation that horticulural clods need to "prune" Mexican grass tree into the classic Phoenix beer keg shape.

Propagation: Usually propagated sexually by seed but germination and establishment are slow.

Disease and pests: Root rot might occur if soil is chronically wet.

Additional comments: Mexican grass tree is a large, beautiful and noble plant for Phoenix landscapes. Like its counterpart D. wheeleri, Mexican grass tree is often misused by landscape designers in the Phoenix area, arranged in tight groupings without sufficient space for them to grow and spread naturally to full maturity.