By Pancy
United Kingdom 
As you all have been very very helpful on my name that tree question , i wonder if any one would know [ why my irises have never bloomed] i planted them three years ago, they were a gift from one of our clients, i have followed all the recommendations to planting. i wait patiently to see what colour they are but nothing. they are in full sun.
9 Jun, 2012
Answers
Exactly and if rhizominous have you planted them so that part of the rhizome is above the surface? planted too deeply they will not flower, at least that is my experience.
9 Jun, 2012
they are rhizomes almost sitting on top of the soil
9 Jun, 2012
Very odd and, sorry, no advice!
9 Jun, 2012
Do you know if the soil is alkaline or not?
Iris do not like limy soils!
Have you fed them? If so with what?
What is in my mind is; the spring feed should be low in nitrogen, if it isn't you might be getting foliage at the expense of flowers.
Another thing is the type of iris, some types flower late on in the season so the ones you have may not be due to flower yet.
Add to that we have had an exceptional year of low light levels and cool conditions and I am finding some of my stuff is flowering up to four weeks later than normal
Try running your forefinger and thumb up the flag ( leaves) to see if you can the formation of a flower stem.
Other than that I am sorry but I can't help you.
You could read this article and it's related links and see if there is anything there than rings a bell.
http://www.thegardenersalmanac.co.uk/Data/Iris/Iris.htm
9 Jun, 2012
thank you for all the advise.the Siberian iris have been exceptional this year so i am really baffled. i will keep an eye on them perhaps they could be late.
9 Jun, 2012
Pancy, the rhizomes are almost sitting on top of the soil is not where they should be, they should be ontop of the soil getting full sun. remove the soil that is covering the rhizomes and ensure they are not shded by each other or neighbouring plants.
10 Jun, 2012
Thank you 2ndhand, i will take all soil away, and neighboring plants. keep you posted.
10 Jun, 2012
What type of iris.
Rhizmous or bulbous?
9 Jun, 2012