This is definitely iris related. When you referred to flats, the first
thing that came to mind were the seedling flats sold here in the U.S.
containing bedding plants, perennials, annuals and groundcovers -
things like that. Those 'flats' turned out to be flatties and look
really amazing. I hope Christian has visited and taken note!
Thanks for the iris blog.
Texas Zone 7b, USA