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Iris prismatica

slender blue iris add to wishlist

Plant types and subtypes: Perennials, Bulbs

Light Requirements: sun, part-sun, part-shade

Water Use: medium

Soil Moisture: moist, wet

Soil Description: acid

Height: 1'-2'

Bloom Time: June, July

Bloom Color: blue

Leaf Color: green

Hardiness Zone: 4, 5, 6, 7, 8

Additional Tags: attracts hummingbirds, bog plant, clumping, colonizing, deer resistant, ornamental foliage, pond margin plant, salt tolerant, stream margin plant, wetland plant

Iris prismatica (slender blue iris)
  • Iris prismatica (slender blue iris)
  • Iris prismatica (slender blue iris)
  • Iris prismatica (slender blue iris)

Pricing & Availability


Iris prismatica

Also known as:

slender blue iris


slender blue flag


coastal iris

Scientific Synonyms:

Iris carolina, Iris prismatica var. austrina


Iris prismatica is a stunning iris that produces large, slender blue flowers that can be up to 4" across. Typically 1 to 2' tall, it can grow up to 3' under ideal conditions. The foliage is very attractive and grass-like, growing a mere 1/4" to 1/2" across.


Slender blue iris is primarily a coastal species, with a few disjunct inland populations. It thrives under wet conditions, and can withstand extended periods partially submerged in fresh or brackish water. It will adapt easily to garden conditions in areas where the soil is kept consistently moist. It is best planted in part-sun or part-shade if the soil is going to be on the dry side, or in full sun if wet. The roots system is rhizomatous and tuberous, and will rapidly form dense colonies under ideal conditions. A perfect choice to grow around water features, or in a moist cottage garden where the grass-like foliage will provide a strong visual accent. Zones 4-8


Propagate from seed or clump division. Tubers should only be partially buried.

Additional Notes

Although its native range is extensive, it is endangered or presumed extirpated in most of it due to habitat loss.

Native Range & Classification

Recorded County Distribution: USDA data

Native Range:

USDA Endangered Status:

  • Endangered: MD, PA
  • Threatened: ME, NH, NY, TN


Kingdom Plantae Plants
Subkingdom Tracheobionta Vascular plants
Superdivision Spermatophyta Seed plants
Division Magnoliophyta Flowering plants
Class Liliopsida Monocotyledons
Subclass Liliidae
Order Liliales
Family Iridaceae Iris family
Genus Iris iris
Species Iris prismatica slender blue iris