The Druids believed that the sun never deserted the holly tree even at the winter solstice. The start of the Celtic Samhain was marked by the departure of both the Earth goddess and the Oak Lord. This left Herne and the Holly Lord to rule over the winter. People decorated their dwellings with branches of holly and other evergreens during the winter in the belief that woodland spirits could find indoor shelter in the greenery during the coldest part of the year. This vegetation was kept inside until Imbole (early in February) when the Earth Goddess returned and life began to spring anew.
~ Patrick Harding, The Xmas Files
Sounds reasonable . . . . .