July through September (late summer) is a good time to dig and reset clumps of iris that are crowded, usually after 3-4 years growth. If you live in an area with a harsh winter climate, your iris may require some sort of winter protection, especially the first year. Iris will thrive without feeding but will respond to fertilization with spectacular results. An application of a well-balanced fertilizer (5-10-5), applied as a top dressing dusted around and in between plants in the early Spring and very late Fall is desirable. Fertilizer can also be applied right after bloom is finished. Any fertilizer application should be light. In general, fertilizers high in nitrogen, including fresh manure, should be avoided because too much nitrogen encourages rot problems. Every 3 or 4 years, dig clumps, remove and discard the old center divisions that have bloomed and replant the new large fans with strong foliage. Use a sharp knife to separate rhizomes, borer holes or diseased looking parts. Trim leaves halfway back to an inverted V shape (^) and also trim roots back to about 4-6 inches. Soak for 1-10 minutes in 10% bleach solution, dry in cool, shady place for a day. If leaf spot is a problem, soak in fungicide for 30 minutes after rinsing in bleach water. Dust any open wounds with sulfur.
Try to plant in a location that enjoys full sun and remember to water moderately. Keep in mind when planting that Devil May Care is thought of as hardy, so Devil May Care will tend to go dormant or grow slowly over the winter months. Ensure your soil has a ph of between 6.1 and 7.8 as Devil May Care is a weakly acidic soil - weakly alkaline soil loving plant.About two months after pollination a seed pod will turn brown and split open. Harvest the golden brown seed and allow them to dry out for a couple more months (Be sure to keep the record of the parents with the seed). In late October plant the seed about 3/4" deep and 1" apart in well drained soil. The planted seed should spend the winter outdoors. The following spring little Iris plants will grow from the seed you planted. Replant and space out the “baby” Iris when they become crowded.
Look to ensure a distance 1.19 inches (3.05 cm) between seeds when sowing - bury at a depth of at least 0.99 inches (2.55 cm) deep.Iris takes its name from the Greek word for a rainbow, referring to the wide variety of flower colors found among the many species.
In some languages, irises are called flags or sword flags, relating them to symbols of heraldry and royalty, hence the original “Fleur de lys” of heraldry. In Japan the shape is seen to express heroism and the blue colour refers to blue blood, so irises play a key role in their spring festival for boys.