Yuccas grow over much of North America; hardiness depends on species. All have tough, sword- shaped leaves and large clusters of white or whitish, rounded to bell-shaped flowers. Some are stemless, while others reach tree size. Best in well-drained soil.
Taller kinds make striking silhouettes, and even stemless species provide important vertical effects when in bloom. Some have stiff, sharp-pointed leaves; keep these away from walks, terraces, and other well-traveled areas. Yuccas are not usually browsed by deer.
Young plants of some species can be used as indoor plants; they withstand the dry indoor atmosphere and will grow well near hot, sunny windows. Give moderate water; feed monthly during growth with a balanced liquid fertilizer. Buy 1-gallon size or smaller; set out in ground when plants become too large for indoors. Successful indoors are Y. aloifolia (but beware of sharp-pointed leaves), Y. elephantipes, Y. filamentosa, Y. gloriosa, and Y. recurvifolia.
Y. aloifolia. SPANISH BAYONET, SPANISH DAGGER. Zones MS, LS, CS, TS; USDA 7-11. Native to the South. Slow growth to 10 ft. by 5 ft. or larger; trunk may be single or branched, sometimes sprawling in picturesque effect. Stems densely clothed in dark green, sharp-pointed leaves to 212 ft. long and 2 in. wide. White flowers (sometimes tinged purple) to 4 in. across, in dense, erect clusters to 2 ft. tall in summer. Moderate water. 'Variegata' has green foliage edged in yellowish white.
Y. baccata. BANANA YUCCA. Zones US, MS, LS, CS, TS; USDA 6-11. Native to the Southwest. Slow growth to 3 ft. high, 5 ft. wide. Foliage clump may have no stem or a short, prostrate one. Thick, stiff leaves to 2 ft. long, 2 in. wide have fibers along the edges. Large, fleshy flowers in late spring are red-brown outside, white inside, in dense, 2-ft.-long clusters. Fleshy, edible, bananalike fruit to 6 in. long. Little water. 'Compactum' is somewhat smaller than the species.
Y. elata. SOAPTREE YUCCA. Zones US, MS, LS, CS, TS; USDA 6-11. Native to the Southwest, northern Mexico. Slow growth to 620 ft. tall, 810 ft. wide, with single or branched trunk. Leaves to 4 ft. long, 12 in. wide. Tall spikes of white flowers in summer. Little water.
Y. elephantipes (Y. gigantea). GIANT YUCCA. Zones CS, TS; USDA 9-11. Native to Mexico. Fast growing (to 2 ft. per year), eventually 1530 ft. tall, 8 ft. wide, usually with several trunks. Leaves 4 ft. long, 3 in. wide, dark rich green. Striking silhouette alone or combined with other big-scale foliage plants; out of scale in smaller gardens. Large spikes of creamy white flowers in spring. Does best in good, well-drained soil with regular water. A variegated form has pale green leaves with broad cream-colored stripes.
Y. filamentosa. ADAM'S NEEDLE. Zones US, MS, LS, CS, TS; USDA 6-11. Native to the Southeast. Stemless plant to 212 ft. tall, 5 ft. wide. Stiff, dark green leaves 212 ft. long, 1 in. wide, with long, loose fibers at edges. Blooms in late spring and summer, with lightly fragrant, yellowish white flowers, 23 in. wide, carried in tall, narrow clusters to 47 ft. or taller. Looks similar to Y. flaccida and Y. smalliana. One of the most cold hardy and widely planted yuccas. Moderate water. 'Bright Edge' has leaves edged in yellow; 'Color Guard' and 'Garland's Gold' have creamy gold leaves widely edged in green. 'Variegata' has green leaves edged with white.
Y. flaccida. Zones US, MS, LS, CS, TS; USDA 6-11. Native to the Southeast. Stemless. Differs from Y. filamentosa in having less rigid leaves, straight fibers on leaf edges, and somewhat shorter flower clusters. Moderate water. 'Golden Sword' has yellow leaves edged in dark green. 'Ivory' has out-facing rather than drooping flowers.
Y. glauca. SOAPWEED. Zones US, MS, LS, CS; USDA 6-9. Native to central and southwestern U.S. To 34 ft. high and wide or larger, with short or prostrate trunk. Stiff, narrow, 1- to 212-ft.-long leaves form a clump 34 ft. wide. Leaves are grayish green, edged with a hairline of white and a few thin threads. White summer flowers bloom on a spike 45 ft. tall. Moderate water.
Y. gloriosa. MOUND-LILY YUCCA, SPANISH DAGGER, SOFT-TIP YUCCA. Zones MS, LS, CS, TS; USDA 7-11. Native to the Southeast. Much like Y. aloifolia; generally multitrunked to 10 ft. tall and 8 ft. wide. Plant is usually stemless in youth. Leaf points are soft and will not penetrate skin. Summer bloom. Good green color blends well with tropical-looking, lush plants. Needs moderate water; too much moisture may produce black areas on leaf margins. Leaves of 'Variegata' are edged in creamy white. 'Bright Star' is a slow-growing dwarf form (to 2 ft. tall, 5 ft. wide) with broad margins of golden yellow.
Y. pallida. PALE-LEAF YUCCA. Zones MS, LS, CS, TS; USDA 7-11. Native to Texas. To 112 ft. tall, 212 ft. wide. Compact rosette of 1- to 2-ft.-long, pale blue-green leaves with thin yellow or brownish margins and a spine at the tip. Branched spikes to 7 ft. high hold many pale green to creamy white flowers in spring. Little to moderate water.
Y. recurvifolia. CURVE-LEAF YUCCA, SOFT-LEAF YUCCA. Zones MS, LS, CS, TS; USDA 7-11. Native to the Southeast. The botanical name of this plant is a bit of a moving target: You may find it listed as above or as Y. gloriosa recurvifolia, Y. g. tristis, or Y. pendula. Whatever its name, it forms a single trunk to 610 ft. tall; it is unbranched in younger plants but may be lightly branched in age. Reaches 68 ft. wide; spreads by offsets to form large groups. Beautiful blue-gray leaves are 23 ft. long, 2 in. wide, sharply bent downward; leaf tips are spined but bend to the touch (they aren't dangerously sharp). Less stiff and metallic looking than most yuccas. Loose, open, 3- to 5-ft.-tall clusters of large white flowers in late spring or early summer. Easy to grow in all garden conditions; give moderate water. 'Banana Split' has golden yellow leaves edged in gray-green.
Y. rostrata. BLUE BEARD YUCCA. Zones US, MS, LS, CS, TS; USDA 6-11. Native to Mexico, extreme southwestern Texas. To 12 ft. tall, 9 ft. wide. The most notable feature is the trunk: up to 8 in. thick, covered with soft gray fuzz (fibers remaining from old leaf bases). Needle-pointed blue- green leaves to 2 ft. long, 12 in. wide. Blooms in autumn, bearing 2-ft. clusters of white flowers on a 2-ft. stalk. Little to moderate water. 'Sapphire Skies' has narrow, flexible, powder-blue leaves; just 4 ft. tall after 10 years.
Y. rupicola. TWISTED-LEAF YUCCA. Zones MS, LS, CS, TS; USDA 7-11. Clump-forming Texas native to 3 ft. high and wide. Sharp-pointed, green leaves reach 2 ft. long; they are straight when young, then twist with age. In spring, stalks to 38 ft. tall bear bell-shaped, creamy white flowers with a yellow-green tinge. Little to moderate water.
Y. smalliana (Y. filamentosa smalliana). ADAM'S NEEDLE, BEAR'S GRASS. Zones US, MS, LS, CS, TS; USDA 6-11. Native to southeastern and south-central U.S. Like Y. filamentosa but has narrower, flatter leaves and smaller flowers. Moderate water.
Y. thompsoniana. THOMPSON'S YUCCA. Zones US, MS, LS, CS, TS; USDA 6-11. Native to Texas. Tree to 610 ft. tall, 5 ft. wide. Trunk (sometimes branched) is topped with an asymmetrical rosette of narrow, foot-long blue-green leaves; old brown leaves hang from its sides. Blooms in late spring, when white to cream flowers with green-tinged petal bases appear on a 4- to 5-ft. spike. Moderate water.
Y. torreyi. TORREY YUCCA. Zones LS, CS, TS; USDA 8-11. Native from New Mexico and Texas into Mexico. Eventually forms a tree to 15 ft. tall, 9 ft. wide. Begins as a rosette of rigid, sharp-tipped, blue-green leaves on short trunks that slowly elongate. White flowers are borne in late spring on a 4-ft. spike. Needs very little water but tolerates wetter conditions.
Y. treculeana. GIANT SPANISH DAGGER. Zones MS, LS, CS, TS; USDA 7-11. Native to Texas and Mexico. Single-trunked or branching tree to 25 ft. tall, 12 ft. wide, topped with symmetrical rosettes of sharp-pointed, thick, stiff, dark green to blue-green leaves to 2124 ft. long. White or purple-tinged white flowers bloom on a 3-ft. spike in late winter or early spring. Little to moderate water.