Growing Louisiana Iris
After purchase care:
Place rhizomes in water just up to the bottom of foliage until ready to plant. You can hold them for about one month this way. Never let them dry out to prevent going into dormancy.
Louisiana Iris should be grown in half to full sun. If grown in beds in full sun, water deeply once a week during dry periods. These iris do not require bog conditions to grow, but will thrive in sites with adequate watering.
Soil condition and preparation:
Soil ph of 6.5 or lower is recommended. Add compost and organic matter to acidify alkaline or sandy soils. If possible, prepare beds a few weeks before planting. Add organic matter and a generous amount of complete fertilizer, such as 8-8-8 (8-10 lbs per 100 sq feet) and work in.
Planting and Dividing:
The growth cycle of La. Iris actually begins in the fall and continues through winter and culminates in a burst of rapid growth and bloom in the spring. In the more colder regions, the foliage will die back in winter and re-emerge in spring. Mulching during winter is advisable in colder regions where ground may freeze. Generally, the best time to plant and divide La. Iris is mid-to-late August, September or October, not long after new growth period has begun.
How to plant new rhizomes:
Louisiana Iris should be planted with about 1 to 2 inches of soil over the rhizome (not like bearded iris which like the rhizome exposed.) 1-2 inches of mulch over the soil is also recommended to help hold moisture while new roots form. Plant in a triangle about 12 inches apart, to allow for room to spread. The rhizome will grow in the direction the fans are facing, and will also put out new shoots on either side of the mother rhizome. They can be left In place 3-4 years to form a nice clump, before needing to be divided again.
Watering: Once new growth has begun in the fall, the beds should not be allowed to dry out. Watering weekly during dry periods is recommended for good bloom in spring.
Fertilizing: A light dressing (2-4 lbs.) 2 months prior to bloom is recommended, and again in the fall prior to growing season. An acid forming fertilizer such as Azalea/Camellia fertilizer can be used if the soil tends to be excessibly alkaline.