Today is the Winter solstice, the shortest day of the year in the Northern Hemisphere and the time when the light begins to return. Traditionally (going way back), this is the British Midwinter Festival of Yule (although winter is just beginning).
Mistletoe (Viscum album) is an important herb right now. It’s berries are poisonous but herbalists use twigs and leaves as an important circulatory tonic, calming to the heart and mind. It is valuable along with others in managing blood pressure.
The association with Midwinter goes back to a Druidic practice. With a sickle of gold the chief druid would cut the golden orb of mistletoe, which, parasitic in the crowns of certain trees including Apple and Oak, would be strikingly visible amongst the tree’s skeletal winter form. The herb would then be used for some ritual or other.