Evidence status: DOCUMENTED custom — deeper origin uncertain
Stand beneath mistletoe at Christmas and everybody knows what is supposed to happen.
That is remarkable when you consider the plant itself.
Mistletoe is not a romantic flower.
It is a parasite.
The Short Answer
The specific custom of kissing beneath mistletoe at Christmas is documented in Britain by the late eighteenth century.
The earliest known explicit reference identified by recent research appears in an English poem published in 1784, in which young men kiss a woman beneath mistletoe.
By the early nineteenth century, Washington Irving described the custom as an established English Christmas tradition, including the rule that a berry should be plucked for every kiss.
Mistletoe had much older religious, medicinal and folkloric associations, but the popular stories linking the kissing tradition directly to ancient Druids or Norse mythology are not securely documented as its historical origin.
What We Know
Mistletoe has attracted human attention for a very long time.
That is hardly surprising.
The plant behaves strangely.
It grows on other trees rather than from the ground.
It remains green when many surrounding plants appear dead in winter.
Its berries emerge during the darkest part of the year.
Ancient writers recorded mistletoe being gathered and used ceremonially.
The Roman author Pliny the Elder famously described Druids gathering mistletoe from oak trees.
The plant also appears in Norse mythology, where mistletoe is involved in the death of the god Baldr.
But none of those ancient sources says:
hang it in the house at Christmas and kiss somebody beneath it.
That part comes much later.
How It Became a Habit
By the eighteenth century, mistletoe had become part of British Christmas decoration.
And somewhere within festive social life, it acquired a new use.
The earliest currently known explicit kissing reference comes from 1784.
By the early nineteenth century, the practice was sufficiently familiar for Washington Irving to describe it during his influential accounts of English Christmas celebrations.
The custom had rules.
A young man could kiss a woman standing beneath the mistletoe.
A berry was removed for each kiss.
When the berries were gone, the kissing privilege ended.
Modern mistletoe has simplified the system.
Nobody checks the berry inventory.
The Story Everyone Tells
One popular explanation invokes the Norse god Baldr.
In the myth, Baldr's mother Frigg tries to protect him by extracting promises from everything in the world not to hurt her son.
Mistletoe is overlooked.
The trickster Loki exploits the omission, and Baldr is killed with mistletoe.
Later romantic retellings say Frigg's tears became the plant's white berries and that she transformed mistletoe into a symbol of love, promising to kiss anyone who passed beneath it.
It is a beautiful explanation for the Christmas custom.
Unfortunately, that final kissing element is not part of the principal surviving medieval Norse versions of the myth.
What the Evidence Actually Says
The Druid and Norse connections demonstrate that mistletoe already carried unusual cultural associations.
They may have helped the plant feel appropriate for winter ritual.
But they do not establish the origin of Christmas kissing.
Recent Smithsonian research identifies the late eighteenth-century English evidence as the first clear historical appearance of the specific custom.
So:
DOCUMENTED: Mistletoe had religious and medicinal significance long before modern Christmas celebrations.
DOCUMENTED: Kissing beneath mistletoe existed in Britain by 1784.
DOCUMENTED: The custom was well established by Washington Irving's time.
PLAUSIBLE: The plant's older associations with fertility, vitality and winter ritual made it attractive for festive use.
FOLKLORE: Norse mythology does not provide a documented direct explanation for the kissing custom.
UNKNOWN: We cannot identify the person or moment that first turned hanging mistletoe into an invitation to kiss.
Different Elsewhere
Mistletoe was particularly associated with British Christmas culture before spreading internationally.
Other countries developed different plants and customs for winter celebration.
And one historical part of the British tradition deserves to remain historical:
women were sometimes socially expected not to refuse a kiss beneath the mistletoe.
Modern custom does not override consent.
A plant hanging from the ceiling has no legal authority whatsoever.
Why It Stuck
Because it gives flirtation a rule.
Instead of someone having to create the romantic moment, the decoration creates it for them.
Look up.
There is the mistletoe.
Everyone laughs.
Someone leans in.
A parasitic plant has somehow become Christmas's unofficial matchmaking service.
Related Curiosities
Why Do We Hang Stockings at Christmas?
Why Do Children Say “Trick or Treat”?
Why Do Italians Wear Red Underwear at New Year?
Sources & Further Reading
Smithsonian Magazine — “How Mistletoe Became a Christmas Kissing Tradition” — identifies the 1784 reference and traces the later development of the custom.
Smithsonian National Museum of Natural History — mistletoe history and biology — older fertility and vitality associations surrounding the plant.
Smithsonian Magazine — “Mistletoe: The Evolution of a Christmas Tradition” — discussion of competing folklore surrounding the plant.
Last checked: 19 September 2026