Plant Preference/Growing Conditions:

The Iris giganticaerulea prefers temperate climate with abundant rainfall. It can tolerate shade but flourishes in full sunlight and in moist, well-drained soils rich in organic matter.

Growth Habit/Description:

Exhibits sturdy, upright stems that typically grow between 3 and 6 feet tall. Its leaves are 30 inches or less long and about 1 1/2 inches wide; they clasp the stem near the base.  The flower petals are large with a deep azure blue coloring. The flowers can be up to 15 cm across. Each bloom has a prominent, yellowish stamen that contrasts with the color of the petals. The fruit type is a capsule, or a dry fruit that splits open along 3 or more lines.

Bloom Season:

The bloom season is early spring, when it comes out of dormancy. It produces flowers from late spring to early summer.

Fall and/or Winter Interest?

No.

Host Plant for Caterpillars?

Iris in general is a host plant for 8 species of butterflies. This includes the Whitemarked Tussock Moth, American Ear Moth, Spotted Beet Webworm, Darker Moodna, Verbena Bud Moth, Burdock Border, White Slant-Line, and Stalk Border.

Other Known Ecological Value?

Yes.   It provides nectar and pollen for pollinators such as bees and butterflies. Its extensive root system helps stabilize wetland soils and prevent erosion. 

Origin of Name:  Iris giganticaerulea translates to "giant blue Iris"

Related Plant Species:   Closely related to about 1500 other species.  While Iris giganticaerulea is native to neighboring Louisiana, dwarf crested iris (Iris cristata) and southern blue flag (Iris virginica) are native to Arkansas.  Louisiana iris can grow up to 5 or 6 feet tall while southern blue flag is about 2 feet tall with 3 foot light blue flowers with a large yellow center.  Dwarf crested iris is considerably smaller with leaves ranging in height from only 4 to 16 inches.  

Use For Food/Medicine:

Its rhizomes have been utilized in herbal remedies, believed to have diuretic and anti-inflammatory properties. Its flowers are also commonly used to make perfumes due to their fragrant quality.

Lady Bird Johnson Wildflower Center.   c 2023.   Plant Database.   Iris giganticaerulea.   [Cited 2025, Sept. 7].   Available from: www.wildflower.org/plants/result.php?id_plant=IR 

Botanical Realm.   c 2024.   Agaves, Orchids, Irises, and Allies (Asparagales).   Giant Blue Iris (Iris giganticaerulea).   [Cited 2025, Sept. 7].  

 Available from: www.botanicalrealm.com/plant-identification/giant-blue-iris-iris-giganticaerulea/ 

Zydeco.   c 2013.   Louisiana Iris Garden.    The species of Louisiana Iris.   [Cited 2025, Sept. 7]   Available from: www.zydecoirises.com/Species/Species.htm 

Musacchia, Joe. c 2015.   World of Irises.   Understanding Louisiana Iris, Part 1: I. giganticaerulea.   [Cited 2025, Sept. 7].  Available from: theamericanirissociety.blogspot.com/2015/03/understanding-louisiana-iris-part-1-i.html 

Entry created by Lydia Gray, September 2025.