Yucca thompsoniana

Yucca thompsoniana closely resembles Yucca rostrata but grows further north, mostly in western Texas and usually on limestone hills and high elevation plains between 900-1800m.
They develop branches right after the first blooming so usually mature plants are branched. In areas where the topsoil is poor, branching may not occur often and tall singles develop.
Under favorable circumstances old specimen can develop up to 10 arms.
Y.thompsoniana remains smaller than Y.rostrata and the leaves are stiffer, shorter (25-40 cm) and greener, especially in nature.
In cultivation the leaves turn more blue and their length increases to 60-80 cm. The leaf width varies from 7-16 mm.
In nature Y.thompsoniana leaves have small yellow lines with fine teeth along the margins, something wild Y.rostrata do not display.
In sharp contrast to Y.rostrata the surface of the leaves feels rather rough.
The inflorescence differs from Y.rostrata: the panicle (40-60 cm long) grows 50-90 cm above the leaves, making the total flower stalk up to 120-150 cm, whereas Y.rostratas flowers start right above the leaves.
In the budding phase the flowers look purple or greenish, unlike the flowers of Y.rostrata.
Frost resistant till -18°C.