All rhizomatous iris and true bulb types require dividing eventually to ensure strong growth as well as allowing the plants to multiply.
Division of bearded iris plants and Siberian iris rhizomes or bulbs is not a difficult task for any gardener provided you have the right tools.
These newly created plants can be replanted in your own garden, planted in pots or given as gifts. Maybe even sold for a small profit, or donated to a school charity or other fundraising activity.
Iris are best divided after flowering, you will need a garden fork and a clean knife or pair of secateurs.
When to divide Iris
Iris can be divided at a number of times during the year, often depending on the climate zone. You will need a garden fork and a clean knife or pair of secateurs.
The best time to divide in colder zones is in spring after the danger of frosts is over
In warmer climates they can be divided in winter.
Some growers like to divide just after flowering when plants are in full growth, they believe it gives them a good start for the next season. And we find this is a good time to divide the rhizomes.
How to divide iris
- Lift the Iris Bulbs (rhizomes) with a garden fork, shake off excess soil and place on a garden bench or in a barrow.
- Loosen the bulbs by shaking, generally they will naturally fall apart into separate plants. To divide some bulbs may require cutting with a knife or secateurs. Cut at least 3 inch sections making sure that foliage and roots are intact for each section
- Cut foliage back with secateurs to 6inches. This reduces stress on the plant.
- Discard any diseased or rotting rhizomes or remove any small areas with a clean sharp knife.
- Bearded Iris like to be planted close to the surface with the top of the rhizome showing.
- Water in well.
Bearded Iris grow well in USDA Zones 3 through 10 in the Eastern State where summers are dry. In the Western States which tend to wetter summers they are best in USDA zones 3 to 8.
They are most popular in the following states; Tennessee, Kentucky, Connecticut, Oregon, Missouri, Ohio, Georgia, South Carolina, Colorado, Indiana, North Carolina, Washington, Wisconsin, Maryland, Massachusetts, Alabama, Michigan, Minnesota, Illinois and California