Answer: Twice blooming iris need the same care the regular bearded iris need. This would be a full sun location (or a minimum of six hours of direct sun including noon) with rich soil that is well drained. They also need to have good air circulation and should be kept weeded. When you plant them, the rhizome should be barely covered with soil and the soil will wash away to leave the rhizome bare. This assures good drainage and helps prevent rotting. Usually you have a bare rhizome to plant, this is set on a mound of soil in the center of the planting hole with the roots draped down the sides of the mound. With a container grown plant, you can set it a little bit higher than it grew in the container, the rhizome will settle a little after planting. If planted too deeply, the rhizome can quickly rot.
Lack of bloom can be caused by starting with a rhizome that is very small and immature or weak, or with a rhizome that is very old and no longer vigorous; or too little sun, or soil that is not rich enough. These plants also like ample moisture when they are actively growing during the spring and for rebloomers, prior to their second bloom season.
Sometimes too it takes a year after planting for the iris to settle in and become established and rebuild their strength to bloom. If you think the iris are planted in a satisfactory location, I would wait and see how they do next spring before deciding to move them. Usually they are trimmed back once the foliage begins to fade in mid summer and can be moved in late summer or very early spring. If you move them again this fall I would not expect bloom until probably fall of 2006 at the soonest.
Enjoy your iris!
Q&A Library Searching Tips