Why do we decorate with mistletoe and holly at Christmas?

Facts to entertain you on Twelfth Night

Jan 05, 2024

You may have already taken down your Christmas decorations (if you had any up in the first place), but today, January 5th, (also known as Twelfth Night), it’s traditional to undeck your halls. In fact, it’s often said to be bad luck to leave Christmas decorations up after this date, though many would disagree. I’m not really one for tradition myself, but I got curious recently about why this superstition exists, and apparently it’s to do with the greenery we use to decorate our homes…

In the past, some people believed that ‘tree spirits’ lived in the holly, ivy and other evergreens that were brought into their homes to decorate at Christmas. I’m sure some people believe this now, too. The story goes that these tree spirits need somewhere warm to shelter during the cold midwinter days. Once the festivities are over, it’s important that the tree spirits are released back outside, or else they'll not only cause mischief in the home, but vegetation will also suffer, causing potential agricultural disasters in our wider communities. Ooh err.

Here are some more facts about a couple of my favourite Christmas evergreens, some festive, some not so…

MISTLETOE

Have you ever noticed mistletoe growing in the wild? It’s actually a parasite, which attaches itself to trees and draws in nutrients from the branches. If you want to get really technical, mistletoe plants also photosynthesise, which makes them ‘hemiparasitic’. Mistletoe and host trees can co-exist, in fact some people grow mistletoe on their own trees at home, but occasionally the plant can cause the tree to become nutrient deprived and die.

In the wild, mistletoe plants need a little help from birds in order to exist, relying on their love of berries, and their subsequent poo, to grow on trees. The word mistletoe actually originates from the Old English version ‘misteltan’, with ‘mistel’ being the Anglo-Saxon word for dung and ‘tan’ meaning twig.

So why all the kissing?! As with most weird traditions, there are several theories about the origin of mistletoe’s association with love and kissing and the plant comes up a lot in mythology. Ancient Druids believed mistletoe was lucky and could protect against evil spirits. The berries were said to contain ‘the sperm of the Gods’ and were thought to be a natural aphrodisiac.

In the past, mistletoe was also thought to have healing properties and was used to treat a range of ailments, from headaches to seizures. Despite the fact we now think of the plant as toxic, some species* have been used in recent years as a cancer treatment.

These healing properties did not apply in Norse mythology. In one well-known story, Loki tricks Hodr into killing his brother, Buldur, using a mistletoe twig as an arrow. In some tellings, Buldur’s mother, Frigg, was so upset about her son’s death that her tears magically turned into the white berries on mistletoe, which would forever symbolise her love for him. In a slightly happier version of the story, the gods were able to resurrect Baldur and Frigg goes on to declare mistletoe a symbol of love, vowing to plant a kiss on all those who pass beneath it.

*There are actually at least 900 species of mistletoe worldwide (some sources say up to 1,500). Some species seem to be more toxic than others.

HOLLY

Holly also has deeply Pagan roots, with Druids, Celts and Romans believing the ability of the evergreens to keep their leaves, even when they were brought inside in winter, assured the return of spring.

Traditionally, the Holly tree is highly sacred in Celtic mythology and symbolises peace and goodwill. Due to its resistance to lightning, it is associated with the Celtic and Norse gods of thunder, Taranis and Thor, and so was planted near dwellings to protect people from lightning strikes.
Druids believed the Holly tree to possess protective qualities, such as guarding against evil spirits and bad luck. Legend has it that bringing the leaves inside during the winter months would provide shelter from the cold for fairies, who in return would be kind to those who lived in the dwelling.
(From the Present Tree)

In Christianity, holly symbolises Christ’s crown of thorns - the red berries representing his blood and the plant’s evergreen nature being a metaphor for life after death. Some say the cross Jesus was crucified on was made of holly and another story suggests holly sprang up from his footsteps.

This is my favourite holly fact, and one that’s been sent to me (usually in the form of this post by Leif Bersweden) multiple times over the past few weeks by friends who know I love a good plant fact…

leifbersweden

A post shared by @leifbersweden

By default, Holly actually grows SMOOTH leaves - they’re cheaper to produce, and intercept more sunlight for photosynthesis. But they’re also vulnerable to being munched by passing deer. Holly naturally grows in the understory of woodlands so needs to be able to build a deer defence rapidly if required.
The way it does this is ✨amazing✨ The DNA in every leaf on a single tree is exactly the same, but Holly has the ability to chemically turn genes on and off in *each leaf* in response to being nibbled.
So the Holly, recognising that it’s being eaten, will turn certain genes on and regrow spiky leaves in place of the smooth ones that were nibbled, to deter the deer when they next come to visit.
So on tall bushes you’ll usually find a selection of leaves that range from smooth ones at the top of the tree - where they’re out of reach of deer - to very prickly ones at the bottom where they need protection. How cool is that?!
And - get this - in gardens and cities Holly leaves are commonly all spiky, because by using hedge trimmers we’re mimicking a herbivore that can reach all the way to the top of the tree.
(by Leif Bersweden)

There’s a great National Trust post containing more holly facts too, if you’d like to learn more about this incredible plant.

I was planning on writing about ivy and fir/pine trees too but my chores are calling me… so perhaps next Christmas I’ll fill you in on those. If you’ve got any festive foliage facts please do leave them in the comments!

Wishing you all a Happy New Year. May your 2024 be nature-filled and evergreen.