Yucca (Yucca filamentosa) plants, also known as Adam's needles, require only minimal care to thrive outdoors in most areas of the United States. Growers value the plants for their sharp, evergreen foliage and tolerance of drought. Yucca plants also produce ornamental flowers that rise above the leaves on tall flower stalks and grow up to 8 feet tall. Slow-growing yucca plants provide a bold focal point in the landscape and gardeners often plant them in groups or borders. Hardy in USDA Plant Hardiness Zones 4 through 9, most of the country can enjoy yucca with just a little care once the plants are established.
Plant yucca during spring after the threat of frost has passed in a location that receives full sunlight and consists of well-drained, moist soil. Space yucca plants 3 to 4 feet apart to allow enough room for their maximum spread.
Apply a 2- to 3-inch layer of gravel mulch over the ground surrounding yucca plants to improve the soil's moisture retention and prevent weeds from growing. Allow at least 2 inches between the gravel and the plant's crown to allow air to circulate.
Water once every 7 to 10 days during spring and summer to prevent the soil from drying out completely. Reduce watering frequency to once every two weeks during fall and cease altogether during winter. Soak the soil to a depth of 4 to 6 inches at each watering.
Feed yucca plants once per year during early spring just as active growth resumes using a balanced 10-10-10 NPK fertilizer. Water lightly before and after applying to release the nutrients into the soil. Follow the manufacturer's directions for the best results.
Prune yucca plants once per year, immediately after flowing has ended, to improve health and aesthetic appeal. Remove the entire flower stalk, as it will remain as dead wood for several years if not removed. Trim away damaged foliage as necessary throughout the year.