I transplanted some yellow and purple iris last year. When they bloomed this year, some of them bloomed with both colors. They are like a Guldens Mustard color. Why did this happen?
Colorado Iris Transplanting
Typically the color change in Irises are driven by some chemical application, such as the use of the herbicide RoundUp will cause color changes. Other wise the reason for a color change is that the irises divided had some less dominent colors in the mix but being crowded kept them held back. Once these less dominent color mixes were in a new and less crowded location, they came forth in bold fashion.