Dividing An Iris Bulb Dividing An Iris Bulb
It is necessary to divide established iris plants every three to four years. As the plant gets older, it gets crowded, reducing air circulation, and is more susceptible to rotting and pest damage. You can easily divide the rhizome of older plants and plant new, younger rhizomes, which will result in healthier plants and abundant blooms.
Step 1–Dig out the Iris Plant
It is best to divide iris plants right after they have finished blooming, which is usually late summer or early fall. To start dislocating the plant, pierce a garden fork or shovel through the ground, a few inches from the plant. Dig all around the plant, pushing the shovel to a depth of 6 to 8 inches under the soil. Tilt the shovel a little when you dig, until the plant is gradually uprooted with the rhizomes. Trim the leaves of the iris to about six inches length. This helps in handling the plant easily, and also diverts most of the water supply to the roots, so they can develop properly. Remove any parts of the leaves that are torn or dented.
Step 2–Clean the Bulb
After uprooting the iris, wash the bulb with the garden hose. This will make it easier to inspect the roots for any signs of rot or damage. Use a sharp, sterilized knife to dispose of any parts of the roots that look mushy or rotten. Some parts of the roots may also have holes due to insect or pest damage. After each cut, make sure you disinfect the knife again, so that the rot does not spread to healthy parts of the rhizome. You can use denatured rubbing alcohol for sterilization. Once you have thoroughly examined the roots and removed all damaged parts, you are ready the divide the bulb.
Step 3–Divide the Bulb
Use the sterilized knife to separate the bulb into different sections, looking for spots where the bulb branches out. Make sure each section is at least 3 to 4 inches long, and has several healthy roots and leaves sprouting from it.
Step 4–Prepare the Planting Spot
Irises thrive in rich, well-drained soil that is slightly alkaline. They also require full sun. You can amend your soil as required, by adding mature compost to the planting spot. If your soil is acidic, add the required amount of dolomite lime to make it alkaline. If you are planting multiple divisions, leave a distance of about one foot between each. Dig out soil from the planting spot to make a pit about 2 or 3 inches deep, and big enough to accommodate the roots of the iris. Create a small pile of soil in the center of the pit. Take a rhizome division and keep it on top of the pile. Arrange the roots on the rhizome downwards, all around the soil pile. Cover the rhizome with soil, leaving about a third of the division uncovered on the top.
Water thoroughly, and you are all set to start enjoying beautiful blooms from your new iris plant.