Iris are easy to grow
This vast family of beautiful perennials is one of the most important of all garden plants. There are hundreds of varieties ranging through almost every color, differing in size, blooming seasons, and even habits of growth and method of propagation. The two most important groups for the average gardener are (1) the Bearded Iris group and (2) the Beardless Iris group. The Bearded Iris group is commonly known as the German Iris and the Beard-less group includes the Japanese Iris.
Within this vast family, there are many different colors, early, midseason, and late flowering, as well as dwarf, intermediate, and tall strains. Every state in the Union, with the possible exception of Florida, can successfully grow irises. Irises demand good drainage and full sun. A good garden soil that will produce corn or potatoes will grow irises, but for the finest flowers and foliage a high- fertility level must be maintained.
Plant root divisions in the early spring or just after blooming. Early fall planting is successful in all but the most northern sections of the country. Divide clumps (as shown in diagram) and plant single rhizomes, spacing them 8 to 18 inches apart according to effect desired. Spade planting hole about 10 inches deep and work 1 tablespoonful of fertilizer into the soil in the bottom of the hole. If the soil is heavy, some drainage material such as gravel or broken pottery should be placed in the hole. Fill the hole with the loose soil and place the root section so that it will not be covered more than 1 inch deep. Most Beardless Irises can also be propagated from seeds.
Iris growers have learned that early theories about plant foods being dangerous to the growth of iris are unfounded. However, they will not tolerate fresh manure or even partly rotted manure in direct contact with the roots. Fertilizer provides all the plant food irises need from the soil for the best growth and beauty. Fertilizer should be scratched into the soil around the plant early each spring at the rate of I tablespoonful per plant (1 pint per 25 square feet of area).
Most irises should be divided every three to five years. Divide when the root clump becomes crowded and the stems become numerous thin and weak.