Shreve's Iris, Southern Blue Flag

Iris virginica var. shrevei

Family: Iridaceae (eye-rid-AY-see-ee) (Info)
Genus: Iris (EYE-ris) (Info)
Species: virginica var. shrevei
Synonym:Iris shrevei
Synonym:Iris versicolor var. blandescens
Synonym:Iris versicolor var. shrevei
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24-36 in. (60-90 cm)


12-15 in. (30-38 cm)

15-18 in. (38-45 cm)


USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

Sun Exposure:

Full Sun


Parts of plant are poisonous if ingested

Bloom Color:


Bloom Time:

Late Midseason (MLa)




Other details:

May be a noxious weed or invasive

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

Patent Information:


Propagation Methods:

By dividing rhizomes, tubers, corms or bulbs (including offsets)

Seed Collecting:

Allow pods to dry on plant; break open to collect seeds

Seed does not store well; sow as soon as possible

Awards (if applicable):

Unknown - Tell us

Foliage Color:

Unknown - Tell us

Bloom Characteristics:

Flowers are fragrant

Water Requirements:

Requires consistently moist soil; do not let dry out between waterings

Very high moisture needs; suitable for bogs and water gardens

Where to Grow:

Unknown - Tell us


This plant has been said to grow in the following regions:

Trinity, Alabama

Geneva, Illinois

Hinsdale, Illinois

Yorkville, Illinois

Iowa City, Iowa

Louisville, Kentucky

Coushatta, Louisiana

Belleville, Michigan

Lake Toxaway, North Carolina

Crossville, Tennessee

Brazoria, Texas

Houston, Texas

Pearland, Texas

Virginia Beach, Virginia

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Gardeners' Notes:


On May 5, 2015, JennysGarden_TN from Collierville, TN wrote:

Mine is growing nicely in my left back porch.


On Apr 2, 2013, rntx22 from Houston, TX (Zone 9a) wrote:

I purchased mine last year at Mercer Arboretum's annual March Mart plant sale. They had a section of native plants and this was included. They are trying to promote gardeners to grow more native plants.
I have found this plant much easier to grow than other irises I own. It is currently blooming prolifically. Each bloom only lasts a day or two but each stalk produces multiple rounds of blooms.
I have it planted in a bed that sometimes gets waterlogged after several days of hard rain (the reason why i chose this plant for this site). The rest of the time I just water it when I'm out watering all my plants. It has done fine in both conditions, though does look better with more water.


On Sep 16, 2011, geneva_illinois from Geneva, IL wrote:

The Blue Flag Iris used to grow along the Fox River (zone 5) in Illinois. It got crowded out by non-native species. The Wildflower Sanctuary in Batavia IL (check out the plants on their web site) is restoring Iris Virginica to the river banks and so are some of the residents along the Fox River like I am. You mostly see the Yellow Flag Iris in this area.