Properly pruning your iris plants is an ongoing project. Unlike your trees, which you'll likely only prune once per year, iris plants need periodic pruning, called deadheading, in order to stay healthy all season long. This article will teach you proper pruning techniques and help you avoid common pruning mistakes.
Deadheading your iris allows the plant to put its efforts into growing healthy stems and leaves, not supporting dyeing materials. Deadheading should be done throughout the growing season, whenever you see flowers that have faded and are drooping. Grasp the drooping flower and make your cut just before the leaves emerge from the stem. Make sure your pruning shears are sharp. Dull pruning shears can bruise or tear your delicate iris plants instead of cutting through the stems in one motion.
Rinse and dry your pruning shears after every use, so they won't transmit disease from plant to plant. As you're deadheading your iris, look for signs of disease on the leaves, such as black or brown spots in the center of the leaves. Cut these leaves off at the stem to keep the disease from spreading.
In the fall and winter, the foliage on your iris plant will begin to yellow and wither. While you may be tempted to cut this foliage away completely, there is no need to do so. The rotting leaves will enrich the soil, and encourage the iris to enter a dormant winter state. The only time you'll need to trim your iris foliage in the winter is if you're planning to pull up the iris rhizomes to transplant them or break them apart. Cutting away the dead foliage can make this step easier. To prepare the rhizomes, cut the foliage to about 6 inches above the ground after the first hard frost. When the ground is completely frozen and your iris plants are dormant, dig up the rhizomes.