I have a large group of yellow Japanese iris. They are 6 feet tall and a healthy green. They have not bloomed for 3 years. The nearby Siberians are doing fine. What's up?

Welcome gwe. I have never grown Japanese, but just for the fact they have been growing for three years without blooming. tells me that they probably bloomed for three or more years prior to that. Which brings up the question of whether they are too crowded. I believe there are several on here who do grow Japanese, so expect you will get more comments.

Hi gwe!! Welcome to the Iris forum. I can't help you with your question -- I do not grow Japanese Irises. But the first thing that came to my mind also is *over-crowding*. Stick around -- you'll get answers from knowledgeable people!!

GWE

If they are a large clump, and have stopped blooming, then they need to be divided. When they get overcrowded they don't bloom as much, or at all.

http://mtpleasantiris.com/cult...

This link of Chad Harris' gives a simple guide to thinning your japanese iris.