Mistletoe transpires to be a nuisance…

Or how too much mistletoe will suck your tree dry (and stop it fixing carbon too)…

It’s the last weekend of mistletoe management and harvest work before Christmas and I’ve been reviewing the orchards we’ve worked in this season. All have been over-neglected, most of the apple trees are in dire need of proper management and all have had far too much mistletoe on them – which is, of course, why we were in them…

Too much mistletoe in a small tree can be bad news, stressing the tree and eventually contributing to its death. And, sure enough, in all of the orchards we’ve worked in recently there have been some newly deceased, but still standing, trees – all with lots of (equally dead) mistletoe. Which makes what we are doing – cutting out excess mistletoe, both male and female plants, regardless of their marketability – all the more important. We don’t want to lose any more of them. I’ve covered management issues here before – and am still looking for your management experiences on the survey at www.british.mistletoe.org.uk

But exactly how does mistletoe stress the tree? Well, one simple example is transpiration – the term used for the passage of water and gases through a plant. Mistletoes – including our European mistletoe Viscum album – transpire more freely than the host tree, forcing a passage of water through the tree’s vascular system from the roots faster than the tree wants to.

This raises interesting issues for the tree in winter, when most would, as most are deciduous, be naturally leafless and therefore not transpiring at all. But the parasitic mistletoe is evergreen – forcing ongoing transpiration throughout the year. And summertime is a problem too – the mistletoe’s leaves transpire faster than the host’s leaves – and so in dry summers the tree will become water-stressed much more quickly if it has lots of mistletoe on it.

There are relatively few studies of exactly how this phenomenon works for Viscum album on apple trees despite it being generally accepted as a major issue. But experimental studies from other host trees with Viscum album certainly support the idea.

Most research has, curiously, been on Pine hosts. Which might sound a little odd to most people – as our Viscum album is usually only seen on deciduous hosts. But there are subspecies of this mistletoe that will grow on evergreens, and one of them, Viscum album subspecies austriacum is a common feature on pines in some parts of Europe.

Recent papers from Spain (Sangüesa-Barreda, Linares and Camarero 2013) and from Switzerland (Zweifel, Bangerter, Rigling and Sterck 2012) have documented the transpiration impacts of this mistletoe – and they confirm that this is a significant problem.

A diagram from the Swiss paper, showing the additional stress when mistletoe is present.
A diagram from the Swiss paper, showing the additional stress when mistletoe is present.

The Swiss study showed that the mistletoe’s stomata – the adjustable pores that all plants have on their leaves to regulate water and gas exchange – were ‘barely regulated’ and so water loss through the mistletoe leaves was substantial. In an effort to compensate for this water ‘leak’ the infested pine trees closed their own stomata. This helped reduce water loss, but not sufficiently enough – and it had the side effect of reducing carbon dioxide assimilation – a gas the tree needs to photosynthesise and grow.  CO2 enters the leaves through the stomata – so closed stomata reduce CO2 uptake.

This is, of course, a double whammy for the pine – reduced water and reduced CO2 supplies – so a real problem for the tree, especially in dry periods. The effect is only serious if there is substantial mistletoe growth – but as mistletoe is spreading more rapidly in the area studied the conclusion is that pine mortality will increase in the area, due to mistletoe spread.

The Spanish study looked at the relationship between mistletoe infestation, intrinsic water use efficiency (iWUE) and the increased atmospheric concentrations of CO2. In theory, because higher CO2 levels mean stomata do not need to open so much, the impacts of closure of host stomata due to mistletoe stress could be offset by there being more CO2 anyway. The study confirmed, like the Swiss one, that mistletoe infestation increased drought-stress in infected trees, but also concluded that ‘rising atmospheric CO2 concentrations cannot compensate for the impacts of drought and mistletoe on tree growth’. Which, to be frank, isn’t surprising.

Mistletoe-overgrowth on apple trees. For more views of these particular trees click this caption.
Mistletoe-overgrowth on apple trees. For more views of these particular trees click this caption.

The overall point of reporting all this? To stress that too much mistletoe, whatever the host, will affect the host’s water and gas exchange, and not in a positive way! Management is needed – especially in smaller hosts like apples.

That shouldn’t put people off growing mistletoe of course –a few growths are unlikely to be a problem. And to reach problem levels your mistletoe growths will need to have been growing for several decades. But if your apple tree looks like these (see right) – you need to do some remedial management – and soon!

(PS There’s a video with some impressively overgrown apple trees in the video on this page... and I’m in it too…)

Refs for those who want to know more….

Roman Zweifel, Sara Bangerter, Andreas Rigling and Frank J. Sterck 2012 Pine and mistletoes: how to live with a leak in the water flow and storage system? Journal of Experimental Botany, Vol. 63, No. 7, pp. 2565–2578, 2012

Gabriel Sangüesa-Barreda, Juan Carlos Linares, J. Julio Camarero  2013 Drought and mistletoe reduce growth and water-use efficiency of Scots pine  Forest Ecology and Management 296 (2013) 64–73


Commercial break:

EMShopTry The English Mistletoe Shop for Grow-Kits, Grow-Kit Gift Cards, Books etc, and mistletoe of course.

Or go direct to Amazon to buy A little Book About Mistletoe – in paperback or Kindle formats

Mistletoe ceremony 8th December

Pagans, Wiccans, Druids and Don’t-Knows assembled yesterday for a reassuring mistletoe ceremony in the Severn Vale. The gods (you decide which ones) were kind to us – the weather was beautiful, and only slightly chilly.

I’m posting a few pics of the preparations here. There are none of the actual ceremony (as we were all taking part). Thanks to Keith for hosting it and Caz for organising it.

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Mistletoe influence changing market rules?

The story as reported on the Time website
The story as reported on the Time website

An 11-year old girl selling mistletoe in Portland (the one in Oregon, not the one in Dorset) may have succeeded in changing the rules at the city’s Saturday Market. Last weekend, after she set up a stall selling mistletoe for $4 a bunch (to raise money for her dental braces) she was told she had to stop, as she hadn’t paid for a stall licence.

Madison Root and her family thought her small operation would be fine, as there are many unlicensed buskers and beggars (‘panhandlers’ in local parlance) active in the market area. But she was told that asking a price, rather than relying on goodwill wasn’t allowed – she could raise money by begging but not from sales!

The resulting publicity led to huge interest in her story, many hundreds of orders, and provision of an alternative sales pitch by a Radio Station. And she’s already raised most of what she needs before evening trying the market pitch again. This video explains in more detail.

Meanwhile the municipal authorities have had to go on the defensive, and are suggesting they might alter the rules to be more flexible in future.

Madison is quoting as saying “It’s not about mistletoe. It’s not about me being kicked out. It’s about all of us, It’s about society accepting begging more than hard work and to set a goal for ourselves.”

But I reckon it’s all about the mistletoe really – which is, after all, a plant species* that symbolises peace, friendship and healing – and isn’t that what she’s achieving?

If you’re in North America you can buy Madison’s mistletoe direct from her website http://madisonsmistletoe.com/  I think she might raise rather more than she expected to…


(*although, of course, Madison’s mistletoe isn’t the original mistletoe species of peace, friendship and healing, as her’s is a North American mistletoe species – but I think we can let that point pass…)

Commercial break:

EMShopBut if you’re in the UK you can get the original mistletoe of legend from The English Mistletoe Shop – as well as Grow-Kits, Grow-Kit Gift Cards, Books etc.

Or go direct to Amazon to buy A little Book About Mistletoe – in paperback or Kindle formats

Loki, the god of mistletoe mischief

Loki – the mischief-maker

The Norse God Loki is, usually, considered a major mischief maker, often evil, and the primary baddie in mistletoe-themed slaying of his fellow-god Baldr.

But he is also often portrayed as helpful and useful, though somewhat mischievous, so what is the truth (can you have a truth about a mythical god?).

Baldr slain with a mistletoe-spear, with Hod brandishing the weapon, overlooked by Loki (looking over Hod’s shoulder)

The Baldr story is fairly damning: Baldr, whose death has been foretold, has been given special protection by his mother (Frigg) who has made all animals, birds and all plants that grow in the soil swear never to harm him.

His fellow gods then amuse themselves by attacking him with weapons that cannot hurt him – until Loki makes a weapon from mistletoe. Mistletoe, which does not grow in soil, did not take the vow, and so can kill Baldr. That’s bad enough, but Loki makes it worse by persuading Hod, Baldr’s blind brother, to innocently make the fatal blow with the mistletoe-tipped weapon, ensuring that Hod gets the blame for Baldr’s death, at least initially.

Many accounts claim that this was Loki’s last act – his ultimate folly, and that he was imprisoned as a result.

But what of his career before this? What did Loki do, and was he good, bad or a bit of both? If you research the details online you’re likely to get very confused – as there are so many differing versions, and traditions, relating to Loki and his fellow gods. Even Wikipedia, normally such a reassuring source for information, has an instantly confusing entry for him – here’s the first paragraph:

In Norse mythology, Loki, Loptr, or Hveðrungr is a god or jötunn (or both). Loki is the son of Fárbauti and Laufey, and the brother of Helblindi andBýleistr. By the jötunn Angrboða, Loki is the father of Hel, the wolf Fenrir, and the world serpent Jörmungandr. By his wife Sigyn, Loki is the father ofNarfi and/or Nari. By the stallion Svaðilfari, Loki is the mother—giving birth in the form of a mare—to the eight-legged horse Sleipnir. In addition, Loki is referred to as the father of Váli in the Prose Edda.

Loki, in a Marvel Comics version

Lots of stuff to think about there, and that’s just the first para!

If you prefer your villains a little less complicated you might try assessing Loki via the Marvel Comics version of him – where he is portrayed as an arch-enemy of Thor, and was even voted the 8th Greatest Comic Book Villain of All Time in an Imagine Games Network poll. And he is a primary baddie in the recent Avengers and Thor: The Dark World films.

Joanne Harris’ new book, The Gospel of Loki

But the older traditions are more interesting than these new comic book-based movies. So what is available, in modern literature, on those traditions? Well, the most interesting-looking offering is not yet published – and we’ll have to wait until after Christmas to read it.

This is a new novel, The Gospel of Loki, by Joanne Harris (best-known perhaps for Chocolat, but also known for her many other excellent books) which is to be published in February 2014.

This tells the story of Loki in the first person, describing him as – “the Light-Bringer, the misunderstood, the elusive, the handsome and modest hero”  – which certainly sounds intriguing!

Here’s an extract where Loki and Thor, travelling together in disguise, reveal their identities…

 Well, a good time was had by all, if you enjoy that kind of thing. We ate, we slept, and in the morning Thor gathered up all the bones from the feast of the previous night and prepared for a breakfast of bread and bone marrow. But on investigating the discarded bones, he saw that a thighbone had already been split, and knew someone had disobeyed.

“What did I tell you not to do?” he said, revealing his true Aspect.

Thialfi opened his eyes very wide. “Wow. Oh, wow. You’re Thor,” he said.

“Yes I know that,” said Thor.

“I knew it!” said Thialfi. “I mean, the Thor. The Thunderer. The thunder god.”

“Yes,” said Thor. “And if you recall -”

“Oh, wow,” said Thialfi. “I love your work. That time you dressed up as a bride -”

“Don’t mention that!” said Roskva.

“Oh. Well, the time you rescued Idun from the Ice People, and -”

“Actually, that was me,” I said.

Roskva’s doe eyes opened wide. “Oh, my gods, you’re Loki,” she said. “You’re absolutely my favourite of all the gods in Asgard. Thialfi, you dope, this is Loki. Loki, the Trickster in person. Thor and Loki, in our house, and we never even suspected !”

“Whatever,” said Thor, still irate. “You disobeyed my specific command. You all deserve to pay with your lives.”

I pointed out that killing his loyal fans would hardly help his public image. By then all the family were bowing, scraping and I-am-not-worthy-ing as if they’d never seen a celebrity before. I was frankly revolted, but it seemed to have an effect on Thor.

“All right, all right. I’ll let it pass.”

Thialfi and Roskva jumped for joy. Roskva brought out a little pink notebook and a stick of charcoal and asked me to write my name inside. Thialfi wanted to feel Thor’s arms, to see if they were as thick as they looked.

“So, how do you get to be a god?” said the father of the family. “Is it something that can be taught? Or is it something you’re born with? Because my son’s always saying that he wants to be a god someday, but I don’t know if there’s a career in it. Not like there is in farming.”

Thor assured him that there was.

“So, did you train?” said Thialfi. “Or were you, like, recruited?”

Thor told him it was a bit of both.

I wonder which recruitment agency that was?

For more of this extract you’ll need to visit Joanne Harris’s blog!

The big question for me is – does the mistletoe incident get a mention? But I’ll have to wait until February to find out (though the book can be pre-ordered now…) 

Mistletoe events – outline news

First week of December – and I’ve not yet reported on this year’s mistletoe events in Tenbury Wells! How was last week’s mistletoe auction? What happened at the weekend? Was the Mistletoe Festival day on Saturday successful. How did the Mistletoe Foundation’s druid ceremony go on Sunday (which was, of course, National Mistletoe Day, Dec 1st)?

Well, I have to admit I don’t actually know – as I wasn’t there. Which is unusual for me, as I have been to every Mistletoe Festival weekend since it was established. But I can’t always be there and I had mistletoe commitments elsewhere this year. This did mean I could actually attend my own town’s Christmas lights and procession event for a change – this tends to coincide with Tenbury. That went well – though there was no mistletoe involved…   And on National Mistletoe Day I was delivering mistletoe for a wedding instead of attending the druid ceremony.

So how was it at Tenbury? Well information online so far is very sparse! Perhaps if I wanted to know perhaps I should have been there!

The Mistletoe Foundation report (on their facebook page) that “Honouring all done and it was a beautiful magical time shared by so many people . Mistletoe blessings to all”. So it sounds as if everything went well at the druid ceremony. But there are no news reports or blogs covering the Saturday events yet – come on Tenbury – where’s the News!!.

“The Druid ceremony went very well. Just a simple ceremony attended by about 50 people, not all them Druid. The healing properties of the mistletoe was sent around the world via the spirit of the Rover Teme. This ceremony was independent of the Mistletoe Foundation who have pulled back from this.”

Last Tuesday’s mistletoe auctions in Tenbury included 750 lots of raw mistletoe or holly (not including wreaths and Christmas trees) – but probably at least half of those were holly, not mistletoe. It would be interesting to see the stats for the proportion of holly:mistletoe over the last few years. My impression is that there is proportionally more holly than there used to be but whether that’s a decrease in mistletoe or just an increase in holly sold I don’t know.

Mistletoe prices were fairly good – averaging £2 per kg for good quality material (good white berries and intact green leaves) but only 50p per kg for lower quality stock (that’s the mistletoe with poor berries, tatty leaves, and a yellowy complexion). In practice that means a 10kg bundle/lot of mistletoe cost £20 if good quality or £5 if not.

The second auction is today – it will be interesting to see if prices differ  – they often do for the second one…

A comment on pricing: Do note that the prices above are, of course, wholesale prices of ‘raw’ mistletoe – and bear little resemblance to the retail price. The retail price is largely a reflection of the costs and labour that goes into ‘processing’ the mistletoe after buying it wholesale  – sorting it, cutting out the waste (which is often most of it – mistletoe has an awful lot of stem, and for every perfectly-pretty sprig there are usually numerous unsaleable ones!), trimming it to suit whatever market you’re selling to, and then packaging it (and in some cases shipping it). So when you buy mistletoe from a shop the price is mostly covering post-harvest and post-wholesale processing.


Commercial break:

EMShopTry The English Mistletoe Shop for Grow-Kits, Grow-Kit Gift Cards, Books etc, and mistletoe of course.

Or go direct to Amazon to buy A little Book About Mistletoe – in paperback or Kindle formats