Nolina nelsonii (Blue beargrass tree)

This easy to grow evergreen yucca bears dramatic, sword-shaped yellow leaves with a dark green edge. Not as staunchly upright as some yuccas, its leaf tips sometimes droop with age. Its foliage color is best from fall to spring. Plants grow to nearly 2 feet in height and 3 feet in width. In summer, it produces a 6-foot-tall spike covered with nodding, fragrant, white bell-shaped flowers.

This dramatic architectural plant is one of the most beautiful variegated yuccas on the market. Its sword-shaped leaves bear bold central stripes of bright canary-yellow against a rich celadon edge. In cool weather, margins are tinged pink, and the entire yellow stripe turns rose-colored on many of the leaves, lasting through early spring. Plants grow to 2 feet wide and nearly as tall. Branched clusters of nodding, creamy-white bells open in mid-summer on stout stems that reach 6 feet tall.

This species has deeply divided, fan-shaped leaves of blue-green to 3 feet across. It bears ivory blossoms on 6-foot-long panicles in summer. It may be shoot-hardy to Zone 6 with a deep layer of mulch. 

This sculptural plant bears sword-like leaves to 24 inches long in shades of blue- or gray-green and maturing to dark green, with smooth margins. In summer, the plant produces 8-foot spikes of nodding, bell-shaped, fragrant white flowers, sometimes tinged purple, to 2 inches long.