Introduction

Spanish dagger makes a dramatic landscape statement, its blue-grey to green, drooping leaves projecting from thick, soft, green stems and spikes of slightly reddish-tinged, white, fragrant blossoms appearing in late spring or early summer (Figure 1). With the sharp needled tips removed with shears, Spanish dagger makes a wonderful accent at entryways or in a shrub border, and plants eventually form attractive clumps. High salt tolerance makes Spanish dagger ideal for seaside plantings.

General Information

Scientific name: Yucca gloriosa

Pronunciation: YUCK-kuh glor-ree-OH-suh

Common name(s): Spanish dagger, mound lily yucca

Family: Agavaceae

Plant type: shrub

USDA hardiness zones: 6 through 11 (Figure 2)

Planting month for zone 7: year round

Planting month for zone 8: year round

Planting month for zone 9: year round

Planting month for zone 10 and 11: year round

Origin: native to Florida

Uses: specimen; naturalizing; border; accent; attracts butterflies; screen

Availability: grown in small quantities by a small number of nurseries

Description

Height: 6 to 8 feet

Spread: 4 to 8 feet

Plant habit: upright

Plant density: moderate

Growth rate: slow

Texture: coarse

Foliage

Leaf arrangement: alternate

Leaf type: simple

Leaf margin: entire

Leaf shape: linear

Leaf venation: parallel

Leaf type and persistence: evergreen

Leaf blade length: 18 to 36 inches

Leaf color: green

Fall color: no fall color change

Fall characteristic: not showy

Flower

Flower color: white

Flower characteristic: summer flowering; spring flowering; pleasant fragrance

Fruit

Fruit shape: oval

Fruit length: 1 to 3 inches

Fruit cover: dry or hard

Fruit color: brown

Fruit characteristic: suited for human consumption

Trunk and Branches

Trunk/bark/branches: typically multi-trunked or clumping stems; can be trained to grow with a short, single trunk; not particularly showy

Current year stem/twig color: green

Current year stem/twig thickness: very thick

Culture

Light requirement: plant grows in part shade/part sun

Soil tolerances: alkaline; sand; acidic; loam

Drought tolerance: high

Soil salt tolerances: good

Plant spacing: 36 to 60 inches

Other

Roots: sprouts from roots or lower trunk

Winter interest: no special winter interest

Outstanding plant: plant has outstanding ornamental features and could be planted more

Invasive potential: not known to be invasive

Pest resistance: no serious pests are normally seen on the plant

Use and Management

Spanish dagger is often confused with Spanish bayonet. Leaf margins on Spanish dagger (Yucca gloriosa) are smooth, whereas those on Spanish bayonet (Yucca aloifolia) are rough. The outer halves of the leaves on Spanish dagger also bend toward the ground, whereas those on Spanish bayonet do not.

Growing in full sun or partial shade, Spanish dagger does well on any well-drained soil and should be watered sparingly, if at all.

The cultivar 'Nobilis' is an improved form with dark green leaves.

Propagation is by division of the suckers or by cuttings of any size at any season. Occasionally plants are grown from seed.

Pests and Diseases

Pest problems include scale and yucca moth larvae, which may bore through and weaken the terminal shoot.

Leaf spot can be a problem in areas with poor air circulation.