Yucca rostrata (Beaked Yucca) is a slow-growing tree-like yucca with upright stems and beautiful shimmering topknot of slender grey-blue foliage. ... Large clusters of white flowers bloom on yellow-orange coloured stalks that rise above the foliage on mature plants in late spring.
Water regularly in the spring and summer growing season, but make sure the plant has excellent drainage and dries between waterings. Water sporadically in the winter. Never let a yucca plant sit in a tray of water.