Regarding reticulated irises that fail to bloom. Many reticulated irises has a strong tendency to produce lots and lots of small rice grain sized bulbs and very few blooming sized bulbs. For this reason many cultivars need frequent replanting, otherwise all you will have is leaves. These are good for the commercial bulb grower that want lots and lots of bulbs, but they are generally not great long term garden plants. They will bloom for one or two years but decline from that. In the garden fewer but larger bulbs is much better.
I recommend 'Blue Note', 'Katherine Hodgkin' and 'Sheila Ann Germany' as they all are very reliable bloomers and have a low tendency to break up into small bulbs. They will bloom very well in spring regardless of what weather the preceding summer offered. Drought and sun or cold and rain, it is all good.
'Blue Note' will still benefit from replanting and dividing, preferably at least every other year. 'Katherine Hodgkin' and 'Sheila Ann Germany' can be planted longer without dividing, the only problem would be if it is possible to obtain virus free bulbs or not. As I mentioned previously, I try to rouge out any suspicious virus striped plants from my own stock of these bulbs.
