LOUISIANA IRIS CULTURE
(and what to do when your order arrives)
Unpack your Louisiana iris rhizomes as soon as you receive them. Water them well and place them in the shade where they are protected from the sun and wind. Keep the plants or rhizomes covered with a moist towel or wet burlap until you can plant them.
Always plant iris shallow with no more than 1 inch of soil covering the rhizome. New plantings should be given lots of moisture until they are established. Some shading is beneficial if transplanting during late spring and summer.
Louisiana iris are very easy to grow as long as a few minimum requirements are considered. They will grow best where they get at least half a day or more of sunshine. Louisiana iris require an acidic soil with a pH of 5 to 6.5 being about right. For alkaline soils, add 2 or 3 pounds of soil sulfur per 100 square feet. They grow best in a prepared bed with lots of organic matter worked into the soil, but will also grow well under bog conditions or even in shallow water.
Louisiana iris should be mulched year around with about 3 inches of some type of mulch. This conserves moisture, discourages weeds and protects the plants from cold in the winter and sun damage in the summer. They are heavy feeders and should be fertilized with a complete fertilizer such as 8-8-8 or 12-12-12 right after the fall planting season and again about 2 months prior to bloom season. Louisiana iris like water and should receive moisture about once a week during the growing season and must not be allowed to dry out during the summer and fall when rainfall may be limited.
In the Deep South, Louisiana iris are usually transplanted from late July through August, September, October and into November. Fertilizer is applied in late September or early October and repeated again in late January or early February to increase rhizome size. Louisiana iris usually bloom here in April. Bloom dates will be about one month later in the upper South and about two months later in the North. Fall fertilization must be done earlier in the North and spring applications must be delayed according to bloom dates. Fall planting dates should be about 1 month earlier in the upper South and about 2 months earlier in the North. Spring planting is often best in the northern section of the country, but year around planting can be accomplished in many areas.
CULTURE OF OTHER IRIS
You can treat Iris virginica, Iris laevigata, Iris versicolor, Iris pseudacorus and Iris ensata in a similar fashion to that of the Louisiana iris with good results. Iris ensata should be moist but not in standing water during the winter, although they can be flooded during the bloom season. Iris siberica likes regular garden soil with a pH range of from 5.5 to 7.0 and lots of moisture. This entire group appreciates some mulching year around. Spuria iris must have full sun and good drainage. Hold back on water in late summer during the dormant season. Spuria iris appreciate a neutral to slightly alkaline pH range. Bearded iris like extremely well-drained soil and are difficult to grow here along the hot, humid Gulf Coast.