Yucca elephantipes, also known as yucca guatemalensis, spineless yucca or giant yucca, is a large succulent that grows in U.S. Department of Agriculture plant hardiness zones 9 through 11. It is also widely grown as a houseplant in other areas. The yucca tree has several long, green, sword-shaped leaves sticking out from the top of a brown multistemmed trunk. Indoors the yucca trees get up to 10 feet tall, and outdoor specimens reach up to 30 feet.
Soil and Placement
Plant yuccas in full sun, at least eight hours a day. Keep the trees away from the foundations of buildings, as they develop large root balls. Plant in well-draining soil. If drainage is a problem, amend the soil with sand to improve the drainage or plant in a different location. If the yucca sits in wet soil it can develop root rot or fungal problems. Grown in frost-free regions, the trees can get up to 30 feet tall. In areas with frost they will be shorter.
Yucca trees are sensitive to overwatering. If they get too much water, the roots will rot and the canes will collapse. Allow the soil to dry between waterings, and water the soil and not the tree itself. In the winter, reduce watering to almost none -- just enough to keep the leaves from wilting. If you see signs of overwatering, such as collapse of the leaves or a mushiness in the trunk, especially around the soil line, reduce watering. Remove any leaves or parts of the trunk that are affected. If the trunk rot is severe, the entire stem may need to be removed.
Fertilizer and Pests
Fertilize the plant only during the growing season, generally late April through late September, with a balanced fertilizer according to the instructions on the package. Do not overfertilize; excess fertilizer can burn the roots. Few pests bother yucca trees. One pest to watch for is scale. If you see the hard, brown spots on the tree, scrape them off with a toothbrush and apply an insecticidal soap to prevent their recurrence.
When keeping the yucca indoors, it needs similar conditions to the outdoor plant. Use a pot just large enough to fit the roots. Yucca plants are not usually kept in pots larger than 17 inches. This helps keep the roots from getting waterlogged. Plant in a mixture of equal parts loamy soil and sand. Water when the top 2 inches of soil dries out, and reduce watering in winter. Keep the plant in bright, direct light. The tree would benefit from being moved outdoors during the summer months and placed in full sun.
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