Yucca carnerosana is also know as Giant Spanish dagger, Carneros, Giant Yucca, Palm barreta, or Palm samandoca and belongs to the Agavaceae family. This tree is native to the southwestern United States and northern Mexico (Coahuila). Yucca carnerosana is a large arborescent plant; it can reach up to 15 ft (4-8 m), with a spread of about 6 ft (1.8 m).
This tree usually has a single trunk which, when trimmed has an average diameter of 20-30 cm. The thick trunk is dark brown with irregular furrows. Sometimes the plant branches after flowering (when about 1-2 m high), developing mostly only two heads growing close together. Branched trunks are rare.
This Yucca has beautiful symmetrical rosettes of leaves. The green sword-shaped leaves are 40-70 cm long and 5 cm in width, but in cultivation they can reach a length of 100 cm forming a symmetrical head. The leaf margin shows a brown line from which thick, curling white filaments are growing. The leaves are a bit dangerous because they are stiff and very pointy. As the leaves dries up they fall along the trunk, creating a funny looking skirt. This skirt can be remove if someone prefers a clean stem. Either way this tree is always very good looking.
The fruit is fleshy, indehiscent, about 10 cm long and 4 cm thick. The Yucca seeds are black, thick, and wingless.The Carneros has an inflorescence of 150 to 200 cm tall, with a scape of 75 to 100 cm long and 7,5 to 10 cm thick at the base. The panicle starts 30 cm above the leaves (towering over them), and have about 20 to 30 branchlets, which are from 15 to 60 cm long. The flower stalk is 5-8 cm thick and the green-white flowers are 5-8 cm long. The Yucca carnerosana blooms in late spring.
Hardiness zones: 8-10 (-10°C/15°F, 1°C/35°F) in winter. Yucca Carnerosana is cold hardy from -12 till -15° C when kept dry. In cool wet winter climates it is better to protect the crown against rain, because it is sensitive to rotting. Like all yucca's they like sun and a well drained soil, in wet climates it is better to remove the panicle after a few weeks, as the flowers fall down in the crown and start rotting.