sounds like you have siberian iris. They often take several years after
dividing and transplanting to settle down and flower well again. Generally
they make their best display after they have made up a fairly large clump. I
don't think I would divide them again until they have been flowering well a
few seasons. I think siberians generally like rich soil - at least more than
bearded iris.
I have three clumps started from store-bought pots, (this is their 3rd year
in the ground), and this was the first year that I got several blooms on
each plant. But the clumps are slowly but steadily increasing, so I have
great hopes for next year.
"HA HA Budys Here" wrote in message
...
I have a couple of clumps of iris but not the bearded type, this type is
standard and grows like a clump of ornamental grass. They're purple. They
didn't flower profusely this season but the green part of the plants is
healthier than it's ever been.

Last time I seperated this huge clump into 2 smaller clumps into "pits" of
very
dark compost but for a couple seasons neither the stalks nor the leaves
would
stay upright as the compost didn't provide a good solid "foundation" NOw
that
the planting medium has naturalized and the plants look sturdy & strong,
they're not flowering.

Do Iris prefer not to be treated to a soft, rich royal meal of home made
compost, when I redivide for better flowering?