Lobo wrote:

Why do we cut the leaves into a fan on iris when we dig and divide them?

The roots are damaged in the process of digging and dividing. I
cut the leaves to reduce the demand on the roots for moisture. For
the same reason, I reduce the number of leaves on a shoot when I
take cuttings of other plants.

Also, my iris leaves sometimes grow quite long. I trim them when
dividing to keep the replanted rhizomes from tipping over since the
reduced roots cannot hold such a large plant upright.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at URL:http://www.rossde.com/garden/