(Image and text from here, an interesting FB page!)"The English practice of wassailing the orchard involves visiting the dormant fruit trees on January 17 (the Old Twelfth Night, before the 1752 change from Julian to Gregorian calendar) and having a small ritual celebration to encourage a bountiful harvest in the coming year. Cider from the last year's crop is used to toast the health of the trees. Traditional songs and dances, bonfires, noisemakers, and general revelry are meant to scare off evil spirits and awaken the trees from their winter sleep."
[Text © 2013 by Sheryl Humphrey. Illustration: "Wassailing apple-trees with hot cider in Devonshire on twelfth eve," 1861, from Illustrated London News.]