Planting in the fall gives the irises time to settle in and develop roots so they can bloom in the spring. You can plant them in the spring, but by doing so you often forfeit the bloom season.

I've planted a lot of Iris rhizomes in the last two weeks - so, what are they doing? Are they growing roots at this time, or are they dormant ?

They will put out new roots and one or two may even surprise you by putting up a bloom stalk. If the ones you planted have been cut back you will see them also putting up new fans..

Hmmmm..... right now they don't seem to be doing anything, and there are no new fans, so they don't appear to be growing at all.

Beardeds also may be divided and replanted immediately after bloom. I prefer to do it then when temperatures are lower. And if I've written the name on a leaf with a Sharpie, it hasn't had time to fade and the correct iris is moved or shared.

Schreiner's has done a terrific job on this page. Tons of info on beardeds, culture, pests, etc. Good pic. of borer damage and the moth/larvae.

http://www.schreinersgardens.com/how-to-grow-care-for-bearded-iris

It will take them a little while to start showing new growth..Don't despair I bet all if fine under th soil..

Bearded iris enter a period of partial dormancy about 6 weeks after bloom and this persists until late summer or early fall, when root activity begins again in earnest. Typically, rhizomes that are planted at that time will have a sufficiently developed root system to support spring growth and flowering. Rhizomes planted in spring will often need a season in ground before they start blooming. The exception is already growing plants available at many nurseries at this time of year - they were potted up in fall and are sufficiently well-developed to produce blooms this spring and early summer.

I have just recently planted a lot of Iris rhizomes - TB, Siberian, Louisiana. right now they are not really doing anything. They are not growing, and there is no sign of new fans developing. I would assume they have gone dormant and will remain so until Fall.

Yeah, it takes a few weeks to see anything happening. TBs just don't seem to do much for a while, but you will see the fans start up some green growth in a few weeks. Might not see much in the way of new fans for quite a while, kinda depends on the plant itself. Some varieties are just much more eager to grow than others.

Do the fans continue to grow all summer long ?

They will grow to full size quickly once they start growing, but when it gets really hot they start to brown & crisp up around the edges. Tall bearded iris can look pretty rough in July & August, their dormant period, & then green up again in the fall. Again, a few varieties of bearded iris can look pretty good even in the heat, others can look downright awful. Of course, I'm talking about what I see here in KY. I think you are much farther north than me so they may all look much nicer in the summer. Siberian & Louisiana iris look pretty good all season, I don't get as much bloom from those though.

Right Now my Siberian and Louisiana Iris are but so low to the ground I can barely see them, and they aren't growing at all.

If its only been a couple of weeks, be patient..there is alot going on underground. Also dont water the bearded iris much..let nature take care of them..Louisianas can take extra water..

Right now in New Jersey, we have Rain - and will have Rain for the next 2 days, so the Beardies will be getting a little wet.