Louisiana Iris Info: How To Grow And Care For Water Iris

Louisiana Iris [Loo-ee-see-AN-uh, EYE-ris] belongs to the family of Iridaceae and is a native to the United States.  

The plant has been named after its native region, Louisiana. It is commonly found growing in damp hillside, riversides, and swamps from Texas, Mississippi and along the gulf coast.

Flowering water Louisiana IrisPin

There is five main species iris that make up the Louisiana iris group:

  • Iris Fulva (I. Fulva)
  • Iris Hexagona
  • Iris Giganticaerulea
  • Iris Brevicaulis (I. Brevicaulis)
  • Iris Nelsonii (I. Nelsonii) 

These Louisiana Iris varieties come in a range of different colors, mostly due to natural hybridization among the species and commercial breeding.

The common names for Louisiana Iris plants include:

  • Water Iris
  • Flag Iris

Tips On Louisiana Iris Plant Care and Culture

Size & Growth

The native Louisiana irises produce beautiful sword-like leaves. 

Mature clumps of rhizomes have the ability to grow around 3’ feet wide. 

When Louisiana irises are grown in warmer areas the foliage is denser. This adds a distinctive architectural interest to consistently moist garden locations and rain gardens.

Flowering and Fragrance

Louisiana Iris blooms sit above the foliage which reaches 2′ -3-‘ foot tall.  The 3” – 7” inch wide flowers arrive in early spring during March and April.

The color of these flowers varies from white, pink, yellow, purple, blue, and rust.

These flamboyant flowers are attractive to bees. The visits of these insects often result in pollination and the production of fertile seed in the irises’ large seed pods.

Light & Temperature

The I. Giganticaerulea (Giant Blue Iris) prefers full sun for at least six hours a day. 

They also tolerate partial shade, but it is best to ensure Louisiana iris culture includes full sun for a few hours daily.

This plant sends out rhizomes during the late summer or early fall.

The USDA hardiness zones of this plant are 6 – 10.

Watering and Feeding

The Louisiana Irises prefers the garden soil to be consistently moist to grow optimally. 

Avoid letting the plant completely dry out as this results in damage. 

These plants like water, growing in dry sites, containers, and raised beds require frequent supplemental irrigation.

Feed this plant with general-purpose fertilizer by following the directions mentioned on the package.

Soil & Transplanting

The I. Hexagona is not very particular about the soil types and thrives in clay soils and poor soil as well. 

However, the pH soil preference of these plants is 6.5 or lower. 

It prefers moist, rich, acidic soil. 

Mulching of organic matter around the rhizomes might also be required during the cold season.

Grooming and Maintenance Tips

The Louisiana Iris doesn’t need a lot of maintenance, other than the usual plant care. 

The flower stalks need to be cut back after the spring blooms. However, ensure to preserve the foliage.

When determining the soil level for planting rhizomes, be sure to give preference to acid soil for the best plant growth. 

Be sure to grow them in moist soil. Provide protection against harsh heat to avoid sunscald. 

It is also essential to surround the Iris rhizomes with mulch during winter freezes to prevent any potential damage.

Other Irises You May Like:

How To Propagate Louisiana Iris?

The propagation of the Louisiana Irises is done through seeds and cuttings or division of the main iris rhizomes.

Cutting or divisions from the parent rhizome produces identical flowers. 

However, in some cases, an unexpected flower color might appear, which is mostly due to other Irises species getting intertwined by the rhizome growth. 

It might also be caused by a seed dropping, which resulted in a new hybrid.

The ideal time for dividing and to plant Louisiana Irises is between August and September.  As fall weather begins to cool in October plants will grow until April when they will begin to flower.

However, transplanting the plant right after the bloom period isn’t recommended.

Follow these steps when planting.

  • Remove all of the Irises from the existing beds
  • Create a new bed for the divided plants
  • Prepare the soil by adding commercial fertilizer and organic matter
  • Replant the divisions on the very same day for optimal growth. 
  • Plant the divisions about 12” inches apart.
  • Water the beds continuously for the initial few days until new growth appears
  • Do not allow the soil to dry out. 
  • Every rhizome grown produces flowers once annually
  • Their offsets blossom in the next year. 
  • Therefore, it is essential to make sure the plant gets plenty of water and provided the best growing conditions to maintain consistent blooms every year.

Louisiana Iris Pest or Diseases

This wildflower doesn’t experience any major disease or pest problems. However, they do face a few.

Rust and leaf miners are two of the most common problems.


Rust appears after flowering in summer on the leaves and stems. The rust looks like lots of small dark brown or reddish spots, usually surrounded by a yellow halo or margin.

Leaves severely infected may die back or become discolored. Flowering is not affected since the rust attacks at the end of the growing season.

Treating with fungicides is not considered worth the effort.

Leaf Miners

The larva of the leaf miners insect tunnel inside the leaves to feed. Their feeding is evidenced by the outer leaves collapsing and white streaks running throughout the leaves and near the base of the plant.

Caterpillars are also a problem chewing on new growth.

Learn more in our article on How To Get Rid of Caterpillars

Iris borers bore into rhizomes but are more of an issue with bearded iris. Control with systemic pesticides.

Be on the lookout for slugs and snails as well, as they might climb up flower stalks and damage the flowers.

Louisiana Iris Uses

The Louisiana Irises look stunning when growing along the streams, creeks, ponds, water gardens, and garden beds. 

The reflection of these blooming Irises in the water is one of the many pleasures during the spring season.

Various gardeners prefer combining these plants with other perennials, annuals, as well as small shrubs to enhance the beauty of the garden. 

This way, when the irises enter dormancy, the other plants continue providing a striking view. 

These plants also attract butterflies, bees, and hummingbirds.

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