Yucca thompsoniana

ucca thompsoniana closely resembles Yucca rostrata but grows further north, mostly in western Texas and usually on limestone hills and high elevation plains between 900-1800 m.
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 than those of Y.rostrata, especially in nature.
In cultivation the leaves turn more blue and their length increases to 60-80 cm.
The inflorescence differs from Y.rostrata: the panicle (40-60cm long) grows 50-90 cm above the leaves, making the total flower stalk up to 120-150cm, whereas Y.rostrata's 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.