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U.S. Forest Service

Our Native Irises: Louisiana Irises

Iris giganticaerulea: Giant Blue Iris

The giant blue iris occurs sporadically within Louisiana, the west edge of Mississippi, and eastern Texas.

Iris giganticaerulea. Note the prominent yellow signal in this view of Iris giganticaerulea. The signal in combination with the dark violet veins direct point the way for pollinators to find the nectarines. Photo by Rodney Barton, North American Native Iris.

Range map of Iris giganticaerulea in the United States. Green-colored states indicate where this species is found. Range map of Iris giganticaerulea.

Iris giganticaerulea has a very large (largest flower of the Louisiana irises), light blue to lavender to purple flower, sometimes white to yellowish-white but generally with a blue to purple color. The sepals are widely spreading, arching downward. The signal is a rich yellow, with a yellow-orange stripe along the pubescent central rib. The petals are semi-erect and are smaller and narrower than the sepals. The flower is fragrant with a musky scent. The inflorescence is multi-flowered with two terminal flowers on an erect stem, arising above the leaves. The bright green leaves are stiff and erect, arising from shallowly rooted, branching rhizomes that can form large colonies.

Iris giganticaerulea is commonly found growing in shallow water in wet meadows, marshes, wet ditches, and bogs.

For More Information

group of Iris giganticaerulea. Iris giganticaerulea in a typical grouping. Note the number of individuals that are not blooming. Photo by Larry Allain, USDA PLANTS Database.