Five days after the first new moon following the winter solstice, Druid priests cut mistletoe with a golden sickle from a special oak tree and had to catch the mistletoe before it hit ground. The plant was distributed among the people to hang over their doors for protection against evil in the coming year.
Balder's mother so loved her son that she exacted a promise from all things never to harm him. Only the parasitic mistletoe did not take a vow. Loki, the trickster god, gave a spear made of mistletoe to Balder's blind brother Hod and helped him aim it at his "invulnerable" brother. Balder was killed. Frigg's tears became the berries of mistletoe. When Balder was restored to life, Frigg made mistletoe a symbol of love.
Mistletoe in Dickens Pickwick Papers:
"From the centre of the ceiling of this kitchen, old Wardle had just suspended with his own hands a huge branch of mistletoe, and this same branch of mistletoe instantaneously gave rise to a scene of general and most delightful struggling and confusion; in the midst of which, Mr. Pickwick, with a gallantry that would have done honour to a descendant of Lady Tollimglower herself, took the old lady by the hand, led her beneath the mystic branch, and saluted her in all courtesy and decorum."
Mistletoe in Washington Irving Christmas Eve:
"Here were kept up the old games of hoodman blind, shoe the wild mare, hot cockles, steal the white loaf, bob apple, and snap dragon; the Yule-clog and Christmas candle were regularly burnt, and the mistletoe with its white berries hung up, to the imminent peril of all the pretty housemaids."
More Norse Lore:
It was a Scandinavian custom that if enemies met under a mistletoe bearing oak tree, they would lay down their arms until morning.
Why Was Mistletoe Held in Awe?:
Mistletoe is a parasitic plant that held its green color throughout the northern winter without even being rooted in the ground. Actually the plant is only partially parasitic since it photosynthesizes but it still attaches a type of root system into the host plant to extract nutrients from the tree. See Norse Myths and the History of Mistletoe
Mistletoe and Druids From Pliny - Natural History:
XVI/95: The druids -- that is what the Gauls call their magicians -- hold nothing more sacred than mistletoe and the tree on which it is growing, provided that it is an oak. Groves of oaks are chosen even for their own sake, and the magicians perform no rites without using the foliage of these trees... Anything growing on oak trees they think to have been sent down from heaven, and to be a signal that that particular tree has been chosen by a god. Mistletoe is, however, rather seldom found on an oak, and when it is discovered it is gathered with great ceremony, particularly on the ninth day of the moon... because it is then rising in strength and not yet half its full size. Hailing the moon in a native word that means "healing all things", they prepare a ritual sacrifice and banquet beneath a tree and bring up two white bulls, whose horns are bound for the first time on this occasion. A priest arrayed in white vestments climbs the tree and with a golden sickle cuts down the mistletoe, which is caught in a white cloak. Then finally they kill the victims, praying to the god to render his gift propitious to those on whom he has bestowed it.
[URL = <http://www.staff.ncl.ac.uk/hermann.moisl/sel248/pliny.htm > Natural History]
Non est omittenda in hac re et Galliarum admiratio. nihil habent Druidae - ita suos appellant magos - visco et arbore, in qua gignatur, si modo sit robur, sacratius. iam per se roborum eligunt lucos nec ulla sacra sine earum fronde conficiunt, ut inde appellati quoque interpretatione Graeca possint Druidae videri. enimvero quidquid adgnascatur illis e caelo missum putant signumque esse electae ab ipso deo arboris.
est autem id rarum admodum inventu et repertum magna religione petitur et ante omnia sexta luna, quae principia mensum annorumque his facit et saeculi post tricesimum annum, quia iam virium abunde habeat nec sit sui dimidia. omnia sanantem appellant suo vocabulo. sacrificio epulisque rite sub arbore conparatis duos admovent candidi coloris tauros, quorum cornua tum primum vinciantur.
sacerdos candida veste cultus arborem scandit, falce aurea demetit, candido id excipitur sago. tum deinde victimas immolant praecantes, suum donum deus prosperum faciat iis quibus dederit. fecunditatem eo poto dari cuicumque animalium sterili arbitrantur, contra venena esse omnia remedio. tanta gentium in rebus frivolis plerumque religio est.