Botanical Name: Eryngium
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Common Name: Sea Holly  
Plant photo of: Eryngium
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Water Saving Tip:

Replace turf with groundcovers, trees, and shrubs. If you have areas where no one uses the grass, patches that do not grow well, or a turf area too small to water without runoff, consider replacing the turf with water-efficient landscaping.

  • Anatomy

  • Culture

  • Design

Plant Type

Perennial, Biennial

 

Height Range

1-3'

 

Flower Color

Blue, Green, Violet, White

 

Flower Season

Summer

 

Leaf Color

Grey Green, Silver, White

 

Bark Color

n/a

 

Fruit Color

n/a

 

Fruit Season

n/a

Sun

Full

 

Water

Low

 

Growth Rate

Moderate

 

Soil Type

Clay, Loam

 

Soil Condition

Average, Poor, Well-drained

 

Soil pH

Neutral, Basic

 

Adverse Factors

n/a

Design Styles

English Cottage

 

Accenting Features

Showy Flowers, Specimen

 

Seasonal Interest

Summer, Fall

 

Location Uses

Perennial Border

 

Special Uses

Cut Flowers, Naturalizing

 

Attracts Wildlife

Birds, Butterflies

Information by: Stephanie Duer
Photographer: JJ Neilson Arboretum
  • Description

  • Notes

This group of perennials is so distinctive; they are sort of thistle-like, but with more refinement and and delicacy. There are several species with many cultivars, ranging in heights from 2 to 4 feet tall and about half as wide. They tend to be erect and stiff, with deeply lobed or toothed leaves, ranging from deep green to nearly whitish blue. Flowers are thistle-like, are frequently set atop showy bracts, and bloom late summer.
Grow in well drained soil in full sun; tolerates poor, sandy soils. Overly fertile soils or over-fertilizing may cause it to sprawl. This is a tap-rooted plant that transplants poorly once established and so is best left undisturbed. Plants are biennial, so in the first year, basal rosettes of foliage form that overwinter as evergreen rosettes. In the second year, plants send up flowering stems, produce flowers and seed before dying. As is the case with foxgloves (Digitalis) and hollyhocks (Alcea), these eryngiums will self-seed and remain in the garden from year to year as if they were perennial unless spent flower heads are deadheaded prior to seed drop. Stock purchased at nurseries is typically in its second year, though you may want to check.