Those are perfect examples! So stunning, and like you, a combo that I wouldn't have otherwise considered without seeing them together! I'm a big fan of blue/white/yellow combinations too. I see what you mean about the Lilies bringing a chaotic feel to the arrangement, although the colors all harmonize beautifully. I think it is because the visual strength of the Lilies lies in their form, which is bringing a confusing look to the whole picture (the tilt of the elongated blooms). Although I think if they were offset a bit, but still a part of the overall planting, that they would shine, as well as provide a nice textural contrast to the others. There's the floral designer part of me again, LOL.
