They flower every year - or should do. You propagate from seed but that takes a long time, usually easier to buy bulbs.

Did you buy them in flower? They often don't flower following years as they need to be baked in the sun so if it is a poor spring/summer then you may only get lots of green and no flower!

I just heard that recently from Carol Klein....on Gw....that we don't get hot enough summers to "bake" them properly....also they need to be planted deeper if they have not been flowering for you. There are some varieties that do flower freely every year....the only one I can remember is Kathleen.......?

..... Hodgkin !
I saw CK talk about them too, i didn't realise that they do best if they're in a hot, sunny site, until i watched that. Does it mention this on the bulbs that you buy ?

Kathleen Hodgkin flowers for us every year 25 miles east on Inverness. The bulbs certainly don't get baked up here! or very rarely. I would agree that if the bulbs were bought in flower then it is possible they wouldn't flower the next year whilst the bulb built up strength. We have a huge variety of Iris reticulata in the garden and never have a problem.

I did not see the Gardeners World program that everyone is getting excited about, but if Carol Klein did indeed say that reticulate irises don't flower every year then she is talking a load of rubbish. As Moon grower says, up here in the north of Scotland we have wonderful displays every year.

I read that after flowering, the bulbs divide and take a few years to build up to flowering strength again. Then, more recently, I heard this can be counteracted by planting them deeper. Is this your experience Bulbaholic?

You are correct in saying that the bulb divides after flowering, Andrew, but the only one that does not flower again, for me, is Iris danfordiae where the bulb breaks down into tiny rice grains. This one is often planted as if it were an annual and replaced every year. Deep planting, I have heard of this but never deliberatly tried it. Our bulbs are maybe a couple of inches below the soil at the deepest.
Now, I am thinking here (always a dangerous moment), our bulbs are left in the ground to bulk up into large clumps. If they were lifted, divided and then replanted they might not flower so readily the following year. I wonder if this is what Carol Klein meant? Does anyone on GOY lift their iris bulbs on a regular basis?

No, my bulbs just get left in situ. My iris reticulata are planted in just about the sunniest spot I could muster but still don't flower every year

How odd...