I don't know what your problem is, but here is what I know about iris.
Maybe it will hit on something to give you the answer.

How deep did you plant it. Iris will do well if laid on the ground, but
prefer to be only half covered with dirt. I don't know what pH they
require, but you might check that. They need to be watered, but not overly
so.

Temperature hasn't been a big problem to me. They survive cold weather very
well. In warmer climates, they can have a bug problem in their root system.
After 3 or so years they need to be dug up, broke apart, and replanted or
composted. If you don't, they will crowd themselves out. Mine quit
blooming after 7 years. After replanted, it takes two years to bloom.

I have them planted on the north side of the house. They get about 4 hours
of sunlight in the morning and 2 or 3 more in the evening. This is the
second year for them, so I will soon find out if they do OK.

Good luck. Dwayne




"Janet Galpin and Oliver Patterson" wrote in
message ...
I have a couple of questions about I. unguicularis


I have a bluish one, maybe 'Walter Butt', which is planted at the base
of a south-facing wall as recommended. It has slowly bulked up. Two
years ago it flowered on and off quite well and last year it was
constantly in flower, a few blooms at a time, for the whole winter.
This year a big let-down. I haven't yet had a single flower and I
wondered if anyone could guess why it might be. I assume it must be to
do with temperature at vital times but whether last summer's
temperatures or the winter's temperatures I haven't a clue.

Secondly, I've rooted an off-cut from it and I'm wondering where to
plant it. I've run out of south-facing wall and I'm wondering whether
it's unlikely to flower (especially judging by this winter's
performance) in a south facing sheltered border among shrubs etc. Any
experience of getting it to flower in less than ideal situations?

Many thanks
Janet G