Purple irises contrast dramatically against lemon yellow peonies. These upscale peonies are extremely difficult to locate but well worth the search because when in bloom they create an emotional high and leave the visitor either speechless or shouting with joy. No one is left untouched by this plant. Over several weeks, the yellow peonies will stop blooming, the purple iris will fade but all of the roses will remain in bloom until the first snowfall in early winter.