Can I Grow Them?
Yes, indeed. There really is no area of the U. S. where Louisiana irises cannot be grown. In very cold climates, such as in the Dakotas or other upper Midwest states, exceptional protection, such as a heavy winter mulch, are important. For the most part though, Louisianas grow throughout the country without the necessity of heroic measures.
The principal cultural requirements are few:
- Ample water, but boggy or swampy conditions are not necessary. Three of the five native species literally did come “out of the swamps,” but all — and certainly the hybrids — are happy in well-watered, garden-variety beds.
- No less than a half day of sun for good bloom. A little shade is a good thing, but full sun is okay with ample moisture. Avoid planting them under trees and in competition with tree roots.
- Tolerant of acid to slightly alkaline soils (despite some authorities who say acid only). Growers in the western stays and other areas with high alkalinity may need to push their soil back to near neutral.
- Lots of fertilizer appreciated, either organic or synthetic. Louisiana irises are heavy feeders. A pound of 8- 8-8 for every ten square feet of irises, or the equivalent, is a good rule of thumb.
- Divide and thin out the plants every few years in the fall, replenish the soil with compost or other organic matter, and incorporate fertilizer. Fall planting is best in most of the country, since, unlike most plants, the irises growth cycle begins in very late summer. In cold climates, they may be dormant below snow until spring, but it is best to get them established in early fall.