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USDA, NRCS. 2012. The PLANTS Database (http://plants.usda.gov, 15 October 2012). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Sisyrinchium angustifolium 'Suwannee'

Blue-eyed grass

FIRST IMPRESSIONS:  Sisyrinchium x ‘Suwannee’ is a low rhizomatous wildflower that forms tufted clumps of narrow sword shaped leaves.  Starry bright blue flowers rise above the leaves to a height of about 1’.  This diminutive beauty prospers in sunny or lightly shaded gardens with moist soils.

HABITAT & HARDINESS:  The identity of Sisyrinchium x ‘Suwannee’ is confusing.  In various publications it is listed as a cultivar of Sisyrinchium angustifolium, as a hybrid between unknown species or even as a new species.

Sisyrinchium x ‘Suwannee’ was found by plantsman Charles Webb on the limestone banks of the Suwannee River in the Florida panhandle.  ‘Suwannee’ is reported to be vigorous and adaptable.  Plants are floriferous with larger than normal flowers and compact habit.

Hardiness rating extends from USDA Zones 6-9.

PLANT DESCRIPTION:  Sisyrinchium x ‘Suwannee’ forms attractive spreading rosettes of narrow iris-like foliage.

The linear leaves are pointed with parallel veins and are 6-8” long and ¼” wide. The semi-evergreen leaves are arranged in overlapping fans like those of iris.

Flattened flower stalks arise from the leafy tufts.  Each branched stem terminates in umbels of starry blue florets that emerge from leaf-like bracts,

‘Suwannee’ is much admired for its floriferous nature. Flower are larger than other blue-eyed grasses and are produced over a longer time period.

The 3/4” florets have 3 pointed petals and 3 identical but slightly wider sepals. These tepals are arranged in a ring around a golden-yellow center.  Dark violet nectar guides radiate from the middle of the flower.

Blooming begins in late spring or early summer and continues for two months or more.  Rounded capsules full of small black seed follow.  The seed are distributed short distances by wind.

Plants rise from coarse fibrous roots or rhizomes to 8-12” height and 12-18” spread.

CULTURAL & MAINTENANCE NEEDSSisyrinchium x ‘Suwannee’ is an adaptable cultivar that thrives in sunny or partly shaded dry or moist sites. Plants tolerate some drought, slightly alkaline pH and wet shaded sites. 

Plants are pest resistant and somewhat unpalatable to herbivores.  This vigorous cultivar quickly expands into dense spreading clumps that are broader than they are tall.

In garden situations, plants persist for a longer time if they are divided every 2-3 years to promote vigor.  Thick mulch layers should be avoided as this can cause crown rot. 

If seedlings are a problem, shear plants back after flowering to remove developing seed capsules.

LANDSCAPE USES:  This is a good choice as a Groundcover, Mass or Edging for a Cottage Garden or Perennial Border.  Sisyrinchium x ‘Suwannee’ has Showy Blooms and Attractive Foliage.  It can be naturalized in Lawns or utilized in Meadow Gardens, Rock Gardens, Low Maintenance Plantings, open Shade Gardens and Wildlife Gardens.

COMPANION & UNDERSTUDY PLANTS:  Try pairing Sisyrinchium x ‘Suwannee’ with Anemone canadensis, Carex flaccosperma, Chasmanthium latifolium, Gelsemium sempervirens 'Margarita', Oenothera fruticosa, Phlox glaberrima ‘Morris Berd’ and Solidago odora.

Sisyrinchium angustifolium’Lucerne’ could be substituted in some garden situations.

TRIVIA:  Halictine bees, Bumblebees, other native bees and pollinating flies seek nectar and pollen from the flowers.  Seeds are eaten by various birds.

This grass-like plant is actually a member of the Iris Family.

This cultivar is sometime known as Sisyrinchium angustifolium ‘Suwannee’ or by the cultivar name ‘Suwannee Purple’.


Height:

8-12 in

Spread:

12-18 in

Spacing:

18 in

USDA Hardiness Zone:

6-9

Bloom Color:

Blue

Sisyrinchium angustifolium 'Suwannee' Characteristics

Exposure

  • Full Sun to Partial Shade

Critter Resistance

  • Deer Resistant

Soil Moisture Preference

  • Moist to Dry

Attributes

  • Bog
  • Naturalizing
  • Ground Cover
  • East-Coast Native
  • Rain Garden
  • Drought Tolerant

Flowering Months

  • June
  • May

Foliage Color

  • Green

Season of Interest (Foliage)

  • Spring
  • Summer

Growth Rate

  • Medium

Salt Tolerance

  • Low

Plants that work well with Sisyrinchium angustifolium 'Suwannee'

Carolina jessamine Carolina jessamine (Gelsemium sempervirens 'Margarita')
Carolina jessamine Carolina jessamine (Gelsemium sempervirens 'Margarita')
Sundrops Sundrops (Oenothera fruticosa)
Morris Berd smooth phlox Morris Berd smooth phlox (Phlox glaberrima 'Morris Berd')
Sweet goldenrod Sweet goldenrod (Solidago odora)

Substitutions for Sisyrinchium angustifolium 'Suwannee'

Blue-eyed grass Blue-eyed grass (Sisyrinchium angustifolium 'Lucerne')