Iris giganticaerulea Small (Giant blue iris)

 Direct scans of I. giganticaerulea.

Photo by Robert Turley

Photo by Harry Wolford taken on Avery Island just south of Lafayette, LA.

"Alba" form. Photos by Scott Caliva.

Habitat: Bayous and other wet area along the Gulf coast of Texas, Louisiana and Mississippi.

Bloom: Late April in Zone 7/8

Description:

• Flowers: d 13-15 cm, erect standards, typical is blue or blue purple, also lighter shades and white, rainsed mid-rib on falls of orange or yellow
• Stem: h 95-116 cm or taller, nearly straight, 2 flowers at apex, singles in axils
• Leaves: h to 90 cm, w 2.5 cm
• Rhizome: w 3-4 cm, bare, 20-30 cm annual growth
• Capsule/Seeds: w 3.5 cm, l 10 cm, green at maturity / large, corky, "D" shaped seed
• 2n = 44
• Comments: Largest of the NA natives. Very similar to I. hexagona except larger. Has been classified as a form of I. hexagona.

• Sun: Full sun (6 hr min.), afternoon shade if any.
• Soil type: Neutral to acid, lots of humus.
• Soil moisture: Moist to wet. Mulch to retain moisture and protect rhizomes from sun burn.
• Feeding: Feed at onset of growth in spring and fall.
• Hardiness: Zone 7 maybe 6. Least hardly of the series. Winter mulch above 8.
• Transplant: Easy in fall or spring after bloom.
• Seed germination: Plant seeds before they dry.
• Comments: Generally easy. Will grow in "border garden" conditions with additional water. Needs lots of room. Grows and blooms well for me, but doesn't reach it's potential height. I lost an unprotected clump to a hard freeze here on the 7/8 border.

Distribution of I. giganticaerulea:

Green indicates the presence of I. giganticaerulea within the state.

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Last modified 11/04