Christmas rose, or Helleborus, is the most wondrous flower of the winter season: the rose that blooms in winter. Its quiet beauty is the first sign of spring. Whether it is the symbolism or the seasonality that's linked it to christmas I haven't been able to find out. In Kivik, Sweden, there's an annual exhibition with thousands and thousands of christmas roses of different varieties.
IMAGE: BERNARD M [Public domain], VIA WIKIMEDIA COMMONS