Tall irises like well drained soil and in full sun all day. Most bearded Irises are deep rooted and the ground should have well rotted oragnic manure incorporated into the lower section. Irises come from a harsh climate and do not require a top dressing, add some grit to the soil to improve drianage. When planting, space about 15" apart with the rhizome lying at the surface and the roots spread out and guided down into the soil. The leaves should be trimmed to ~6" to prevent wind rock while plant is settling in. They should be watered and not allowed to dry out in the first weeks after planting. After that they should only need watering during long dry spells. Leave them fully exposed in the winter frosts and don't cut the leaves back ... you may be reducing next season's flowers. Otherwise simply maintain clean and tidy, remove any dead foilage. Do not cover or they will rot. After 3 to 4 years they may become overcrowded, they can be lifted after flowering and before the first frosts of autumn. The rhizome can be broken or cut into sections ready for planting. Discard the parent rhizome. Have grown sucessfully in pots and taken indoors when in flower adorn the breakfast table