Agave attenuata Spineless Century Plant

Introduction

More common in California landscapes than Florida, spineless century plant is more suited for smaller landscapes due to its smaller stature than the century plant (Figure 1). Foliage is a soft, light blueish-green and does not terminate in a spine. The emerging group of leaves forms an attractive cone shape in the center of the plant. It can be included in gardens frequented by children, whereas the spines on the century plant can be hazardous with youngsters nearby.

General Information

Scientific name: Agave attenuata

Pronunciation: uh-GAW-vee at-ten-yoo-AY-tuh

Common name(s): spineless century plant

Family: Agavaceae

Plant type: shrub

USDA hardiness zones: 9 through 11 (Figure 3)

Planting month for zone 9: year-round

Planting month for zone 10 and 11: year-round

Origin: not native to North America

Invasive potential: not known to be invasive

Uses: border; accent; mass planting

Availability: somewhat available, may have to go out of the region to find the plant

Description

Height: 2 to 3 feet

Spread: 3 to 4 feet

Plant habit: round

Plant density: open

Growth rate: slow

Texture: coarse

Foliage

Leaf arrangement: alternate

Leaf type: simple

Leaf margin: terminal spine

Leaf shape: lanceolate

Leaf venation: none, or difficult to see

Leaf type and persistence: evergreen

Leaf blade length: 18 to 36 inches

Leaf color: blue or blue-green

Fall color: no fall color change

Fall characteristic: not showy

Flower

Flower color: white

Flower characteristic: flowers periodically throughout the year

Fruit

Fruit shape: oval

Fruit length: 1 to 3 inches

Fruit cover: dry or hard

Fruit color: brown

Fruit characteristic: persists on the plant

Trunk and Branches

Trunk/bark/branches: not particularly showy; usually with one stem/trunk

Current year stem/twig color: not applicable

Current year stem/twig thickness: not applicable

Culture

Light requirement: plant grows in part shade/part sun

Soil tolerances: alkaline; clay; sand; acidic; loam

Drought tolerance: high

Soil salt tolerance: unknown

Plant spacing: 36 to 60 inches

Other

Roots: usually not a problem

Winter interest: no special winter interest

Outstanding plant: not particularly outstanding

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

Use and Management

Spineless century plant is a hardy survivor, tolerating heat, drought, and moderate salt exposure. Little irrigation is needed once the plant is established. It grows best in full sun but can adapt to some shade. After 10 years or more (though not a century), a lofty flower spike is produced, with terminal panicles of pale yellow to white blooms. The stem producing the flower dies soon after. Plants can be grouped together in a mass or planted alone as a specimen in a rock garden. Larger commercial landscapes have room for multiple mass plantings which can create a dramatic impact.

Propagation is by detaching the well-rooted suckers appearing at the base, or by uprooting germinating seedlings near the plant.

Design Considerations

The bold form and coarse texture of the spineless century plant make it perfect as a specimen plant in highly visible spaces in the landscape. Use with companion plants that are softer, with small foliage and mounding or spreading forms to contrast and highlight the stiff, upright form of the leaves. Pairing with plants that have more texture in the foliage will also contrast with the smooth, stiff leaves. To highlight the soft blueish-green in the leaves use plants with dark green foliage or plants with small to medium flowers with cool, bright colors, such as purples, blues, and deep corals. Another option is to complement the soft green with soft yellow or white wispy grasses. Large masses of low-growing companion plants around the base or in front of the century plant will create a nice setting to show off the form.

Pests and Diseases

Few problems appear to affect most specimens.