I have 7 years experience of growing Blue Moon and 3 years of growing "Twice". Some have told me that the two are "similar" or "very similar". But I would say that there is no difference at all between the two, except that the later variety produces more blooms. The colour, shape, size, fragrance and foliage are all identical. This is what one would expect if "Twice" was intended as an improved version of Blue Moon, which is what I have read in the online catalogues.
