Iris schactii

Help please. I decided to plant up an old stone trough I have with alpines. I purchased an iris schactii in April and planted it in suitable alpine medium (JI no 2 with plenty of added grit). The iris has not yet flowered but what concerns me most is the state of the foliage as seen in attached photo. I have dig up the iris and put in a separate terra cotta plant pot. The rhizomes seem to be fine. The foliage situation is not improving. Any suggestions as to cause and remedies?
Thanks for any advice

 

Where are you in the country?
As far as I can see this particular iris comes from Anatolia and likes well drained soil, full sun and prefers dry, hot summers.
The picture looks as if the molluscs have been munching leaving the fibrous parts of the leaves.
It certainly won't like being wet in winter.

 

Thanks I am in the east Midlands UK.
The trough is south facing and in very gritty compost and trough has drainage holes too . I wondered about slug/ snail damage but nothing else in trough affected. I intend to put in small frame over winter. Do you believe foliage will regenerate or not?