After growing in the ground for 3 – 5 years flowering Iris plants need dividing. This will keep plants healthy and blooming. Below we share 8 steps on diving and replanting Iris clumps.
1. Select the clump you wish to divide and replant and cut the foliage down to a height of 6” to 8” inches.
This is done primarily for easier handling when separating the rhizomes.
Do one clump at a lime so that varieties will not be mixed.
2. Dig the clump, making sure that you label it properly. Lift it carefully, not breaking rhizomes or too many roots.
Then wash all soil from roots and rhizomes with a hose. Do not let roots dry out while separating.
3. The first separation is into clumps of three or four fans—note the original rhizome in the center, which will be discarded.
Divisions of this site will give an immediate show in the garden, but a re-division will be necessary within two years.
4. Separations of single and double fans will not have to be divided again for three to four years.
These are made by cutting with a sharp knife, making sure that a portion of the rhizome and roots is left with each fan.
5. One overcrowded clump has provided us with many divisions. Each one will flower the following year.
At this stage, be sure that each fan is properly labeled. These fans are now ready for planting.
6. Prepare the soil to a depth of 10” to 12” inches, incorporating compost or peat moss and complete plant food.
Prepare a hole for the plant so that roots are well spread out, a little deeper at the ends. Do not overcrowd roots in the hole.
7. Cover the rhizome with soil to complete the planting. Iris rhizomes should be planted just below the surface of the soil. The ground should be moist but not soggy wet.
Make sure that soil is formed tightly around each rhizome.
8. A large pattern of clumps in a border should be planted with the fans facing to the front. Also, leave room for the clump to increase in size.
Place fans from 8” inches to 2′ feet apart – closer planting gives a quicker garden effect.