Expert: Kenneth Joergensen - 7/28/2004

Question
Zone 5, I need to separate iris, which are crowding roses.  Is it like day lilies, dig, pull apart and replant?

Answer
Yes pretty much excep the iris grow from a rhizome (root).

Dig the iris by using a garden fork or shovel and make sure you get under the rhizome (root). Lift the entire clump to the side and was soil off with garden hose so you can see what you do.

The iris clump will usually consist of a "star-shaped" pattern where individual roots (fans) are connected to the middle. Cut each iris root from the community with a sharp knife. make sure each root section has one set of leaves (also called "fans" due to their fan shaped). Do not cut the roots off. Normally you cut off the outer iris rhizomes (with fans) but discard the middle which is the old parts which stopped flowering.

Replant 1" deep, or so that the top of the rhizome is just as soil level. do not plant too deeply. Plant in well draining soil in full sun, but keep well watered until established. Space new divisions 12-18" apart on center (18" allows you 3-4 years without having to divide again).

This is the right time to transplant / divide iris, because the iris needs 3 months to reetablish itself.

I can email you a copy of what an iris root looks like so you know what to cut out. I don't have the pictures at work and will need to provide them tonight when I get home. Let me know if you would like to see them.

Kenneth