Your question intrigued me enough to do some research. The blooms of Marianne Davey range from white to cream, with a yellowish tinge in the center. In some photos on the Web, the creamy-white color of the blooms verges on pale yellow, so I can understand why someone might expect the blooms to be yellow. They're always unmistakably white in my garden, but with a tiny bit of yellow in the center.
