If you have those 'traditional' dark purple irises, they need to be divided pretty regularly. I don't know why, but they seem to flower far better after being chopped up, half thrown out, and replanted.

I don't think you need to do that with the newer, fancy varieties.

I have a mix of different iris varieties in this garden. I did divide them a couple of years ago and there's still plenty of space between them...I guess we'll wait and see if, between fertilizer and exposing the rhizomes more will be all it takes...I guess I was hoping for a smoking gun or an epiphany...:)

I divided my Iris up a couple years ago too, and haven't had many blooms from the originals since then. But the transplanted offshoots bloomed great last year. Even had some funky new colors show up with some of the babies. I'm not sure how that works...

Besides keeping the grass out of them, I don't do much for those. Usually try to keep them mulched well, and incorporate some compost into the soil around them now and then. To encourage more/better blooms, I would try adding something that would give them a phosphorous boost once a month or so, and maybe some potassium too. Something with an NPK ratio that's close to 1:3:2. I don't know if it will work, but thats what I would try first...

Les

About 12 years ago, we re-did a garden bed that had a substantial patch of the traditional dark blue iris, and I broke them up and planted them all along the edge of our pond - on the vague theory that the species originated in flood plains. Anyway, the first year after transplanting, they were spectacular, but the number of flowering plants has steadily declined over the years, now I'm lucky if one or two, out of hundreds of plants, flowers.

However, they have done a great job of stabilizing the pond bank.

Thanks Les for your advice and will try the other fertilizer too. The mulch thing though I've also done but it ends up covering the rhizomes which may have been part of the problem before. But as David points out, it may also be that I just won't get a lot of blooms. That would really stink given how much time my son and I spent planting them. Oh well, we'll see how they do this Summer and if they don't do well again I'll have to reconsider what to do with them.

Karen, you probably know this already... but I didn't until someone explained it to me. So just in case...

Are you pinching the flowers off after they bloom? If not, you might want to try that. I'm in the habit of doing it in the evenings, just before dark... and they are usually on their way to make new ones by the next day. Sometimes I'll have 3-4 blooms on one plant at a time... so its not hurting them any.

I only let the flowers stay on the plant when it gets really late in the year.

Les

Wow, Les. I did NOT know that. I always learn something on this forum. Thx!

Last year was a very bleak iris year for me, even though I separated my irises recently. I did not water enough over the winter. I am hoping I get more flowers this year.