Louisiana Irises natural habitat is the wetlands of Louisiana, USA, in some of the richest soils in the world, growing in usually poorly drained areas and covered with shallow water during much of the growing season. Then through summer, water drains off / evaporates and rhizomes are protected from heat by leaves and other vegetation (acting as a mulch).


  • Louisiana Irises have tall stalks between 75cm to 1.5m in height
  • Fast growing, they are hardy and vigorous
  • Blooming at the same time as the Tall Bearded Irises or slightly after
  • Louisiana Irises are summer dormant


  • Louisiana Irises require full sun with some afternoon shade
  • Lifting and replanting is required every 3-4 years
  • They are a frost tolerant species
  • During growing season they should have a good soaking at least once a week, with at least 2.5cm of water. The soil needs to remain damp constantly


  • Louisiana Irises do not like lime at all and very little nitrogen (don't use rose fertiliser)
  • Animal manure (cow / horse) can be applied along with compost
  • An azalea or camellia mix can be applied
  • Louisiana Irises like acid soil, pH 6.5 to 7.2
  • Alkaline soils can be improved by addition of sulphur or adding organic matter
  • Dressings can be applied:
    • mid-winter, during bloom season, at a rate of 100 grams per square metre
    • late summer / early autumn, when the new foliage appears, at a rate of 300 grams per square metre


Planting should be done after bloom time, either late summer or early autumn.

  • If growing Louisiana's in water:
    • Place rhizome in a 45cm diameter pot with a depth of 20cm
    • Plant the rhizome 2-5cm from the surface
  • If planting at the edge of a pond:
    • Plant slightly above the high water mark and secure rhizome 5cm below the surface, 1m apart.
  • If planting in garden bed:
    • Create a trench to hold the water, plant 5cm deep and mulch over plant

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  • Foliage may tan or get black spots during summer. Avoid overhead watering during humid months.
  • In humid regions Leaf Miner can cause foliage loss and particularly affects plant growth. This is caused by an insect inside the tissue near the base of the leaf. It needs to be controlled by systemic treatment, spraying the whole bed in winter or early spring will control the insect for the whole season.