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Agave-leaved Sea Holly

Eryngium agavifolium

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Agave-leaved Sea Holly (Eryngium agavifolium) at Roger's Gardens

Agave-leaved Sea Holly foliage

Agave-leaved Sea Holly foliage

(Photo courtesy of NetPS Plant Finder)

Plant Height:  24 inches

Flower Height:  4 feet

Spread:  4 feet

Sunlight:  full sun  partial shade 

Hardiness Zone:  5b

Other Names:  Agave Leaf Sea Holly

Description:

A distinctive sea holly with unusual and attractive agave-like foliage that is toothed and shiny; tall stalks end in small, green thistle-like flowers in late spring, that mature to a lovely brown in fall; tolerates hot dry sites; great in mass plantings

Ornamental Features

Agave-leaved Sea Holly's attractive serrated sword-like leaves remain dark green in color throughout the season on a plant with a mounded habit of growth. It features unusual clusters of grayish green ball-shaped flowers at the ends of the stems from late summer to early fall. The flowers are excellent for cutting.

Landscape Attributes

Agave-leaved Sea Holly is an herbaceous perennial with a mounded form. Its relatively fine texture sets it apart from other garden plants with less refined foliage.

This plant will require occasional maintenance and upkeep, and is best cleaned up in early spring before it resumes active growth for the season. It is a good choice for attracting bees and butterflies to your yard, but is not particularly attractive to deer who tend to leave it alone in favor of tastier treats. Gardeners should be aware of the following characteristic(s) that may warrant special consideration;

  • Self-Seeding

Agave-leaved Sea Holly is recommended for the following landscape applications;

  • Mass Planting
  • Rock/Alpine Gardens
  • Border Edging
  • General Garden Use
  • Container Planting

Planting & Growing

Agave-leaved Sea Holly will grow to be about 24 inches tall at maturity extending to 4 feet tall with the flowers, with a spread of 4 feet. Its foliage tends to remain dense right to the ground, not requiring facer plants in front. It grows at a medium rate, and under ideal conditions can be expected to live for approximately 10 years. As an herbaceous perennial, this plant will usually die back to the crown each winter, and will regrow from the base each spring. Be careful not to disturb the crown in late winter when it may not be readily seen!

This plant does best in full sun to partial shade. It prefers dry to average moisture levels with very well-drained soil, and will often die in standing water. It is considered to be drought-tolerant, and thus makes an ideal choice for a low-water garden or xeriscape application. It is not particular as to soil pH, but grows best in poor soils, and is able to handle environmental salt. It is highly tolerant of urban pollution and will even thrive in inner city environments. This species is not originally from North America. It can be propagated by cuttings.

Agave-leaved Sea Holly is a fine choice for the garden, but it is also a good selection for planting in outdoor pots and containers. Because of its height, it is often used as a 'thriller' in the 'spiller-thriller-filler' container combination; plant it near the center of the pot, surrounded by smaller plants and those that spill over the edges. It is even sizeable enough that it can be grown alone in a suitable container. Note that when growing plants in outdoor containers and baskets, they may require more frequent waterings than they would in the yard or garden.

 
 
Hardiness Zone Plant Height Minimum Sunlight
Characteristics
Massing  Rock  Edging  Garden  Container 
Applications
Flowers  Foliage Color  Texture  Attracts Wildlife 
Ornamental Features