Virtues: Excalibur yucca has all the tenacity of other Yucca filamentosa varieties, but with a more compact size and a unique bluish color. Its smaller, more uniform shape makes it a good choice for small gardens and tight spaces in the border, where it adds a unique texture with its spiky leaves. Highly drought tolerant and virtually unkillable, this yucca is a succulent that survives USDA Zone 4 winters if given protection. It is highly deer resistant and attractive to butterflies, too.
Common name: Excalibur yucca, Excalibur Adam’s needle, Excalibur bear-grass
Botanical name:Yucca filamentosa ‘Excalibur’
Exposure: Full sun to part shade
Season: Spring through fall for best foliage, summer for flowers
Flowers: A thick, tall scape will rise from the center of the plant in midsummer, reaching to 5 feet tall, and creamy white bell-shape flowers will open from its top. Blooming may not occur until the yucca reaches full maturity, and then it will be best and most reliable in full sun. These flowers draw butterflies, moths and hummingbirds.
Foliage: Excalibur yucca boasts dusky blue, sword-like leaves with curly white filaments lining their edges.
Habit: This yucca remains a tidy rosette of foliage that hugs the ground. (There are tree-form yuccas, in comparison.) The rosette reaches about 2 feet tall and 3 feet wide. It is an evergreen perennial, but it will look a bit ragged and limp during the coldest months of the year, particularly in the northern part of its growing range.
Origins: Introduced by Walters Gardens, ’Excalibur’ is a selection of the species Yucca filamentosa, which is native to the southeastern United States.
How to grow Excalibur yucca: Site in full for the best foliage color and flowering, though it will grow and possibly bloom even in part shade. Plant in poor to average soil with good drainage. Like all Yucca filamentosa, it is highly drought tolerant once established, possessing a deep taproot that allows it to find ground water in dry times (and makes it difficult to relocate, so choose its position wisely). Reliably hardy in USDA Zones 5–9, but it is reported to survive Zone 4 winters if it is covered with a winter mulch, such as shredded leaves.
Image courtesy of Walters Gardens