The pink edge/coloring is apparently over a white base. The degree of pink and rose edging development is quite dependent on cool nighttime temperatures starting about two weeks before and leading up to bud opening. If nighttime temperatures are very warm, they can literally reduce edging like that to just a hint of color, or in some cases, no edging at all. A classic example of this is cultivar Tropical Isle which during warm nights leading up to bloom will not have that pretty rose edge. Another would be Saltarello which won't develop a peach blush. There may be other factors that I don't know about, but I'll hang my hat on the warm nights. Watch to see what happens next year with your 'Edge'. I'll ask around also.
