Rick's secret is green manure followed by solarization. And they regularly rotate plots. He and Roger grow irises as well as any one. When they were on the tour for the National Convention the clumps of guest iris were some of the best I have ever seen.
Check out his Facebook Page and scroll down to the aerial photo of the garden and notice the fallow strips between the iris. Notice how much sun they get.
https://www.facebook.com/super...