It’s August! Time to spot the six scarce, under-recorded in the UK, mistletoe insects! Which I discussed at a Biodiversity Workshop in Glastonbury a couple of weeks ago.
But no, not yet. It’s August, the silly season for news. So here’s some silly news instead.
Last night I watched the finale of the current Doctor Who series… and there was mistletoe in it! Understated, unremarked-on, but definitely there and used almost-certainly-deliberately (in my view) in background shots.
Why deliberate? Well it’s a distinctive plant, always gives that extra something to a landscape view. I’m attaching some screen-shots (full size below the text) which I hope show this.
And it could even have been, dare I say it, a very subtle reference to mistletoe traditions and previous Doctor Who.
This Who episode showed it on a ‘Solar Farm’ making up one entire floor (of many hundreds) of a 400 mile long, 100 mile wide spaceship. Growing on apple trees in a rural landscape that looked just like the Welsh countryside in Monmouthshire (I wonder why that is…?). And with a traditional, no high-tech, agricultural system, so traditions would seem relevant.
Mistletoe is, according to tradition, a plant of protection, used against evil beings and to gain access to forbidden areas (like the Underworld, in which Aeneas had to carry mistletoe for entry and exit).
The main shots towards the end showed a mistletoe-laden tree next to one of the lift doors, that connected the floors of the ship, through which there was a constant threat of cybermen. And, down below somewhere, was the Doctor, on a floorful of dead cybermen, not unlike the underworld really. So, if one credits the production team with a bit of mistletoe knowledge, that lift door might have been positioned there for protection? Or maybe just for photogenicity?
The Who team have used mistletoe for protection before, way back in 2006 with David Tennant, when a room coated with varnish made from mistletoe protected Queen Victoria (don’t ask) from a Werewolf.
After Christmas mistletoe tends to fade away for most people – until Christmas comes round again of course. But for those who grow mistletoe, deliberately or by chance, January is a good time to think about any management that might be needed.
Small amounts of mistletoe are not a problem for the host tree, even though mistletoe is a parasite that takes over the branch it is growing on. But large amounts can become a significant, even life-threatening, burden for the tree, and these need to be managed.
January, February and March, with the host tree still leafless, are ideal for mistletoe management as the mistletoe can be readily seen and assessed. And there isn’t the temptation, present before Christmas, of only cutting the most attractive berried branches. Mistletoe pruning now is just pruning – not cutting for Christmas decorations!
But how often is mistletoe managed (judging by some old orchards in the Severn Vale a lot isn’t!)? And how is it done? I know how I do it and how I advise others, and I’ll be talking about that in the blog over the next few weeks. But in general?
Finding out how (and if) other people manage mistletoe was one of the aims of the Mistletoe League project I set up a few years ago. That project, basically some questionnaires about mistletoe management in orchards and gardens, was re-vamped this winter, with a new simpler (I think) website and new questionnaire forms set up via Google.
So, if you have mistletoe in your orchard or garden why not spend a few minutes looking at the website and taking part in the questionnaire? Results, when there are enough of them, will be made available for all.
The issue of ‘too much mistletoe’ has been on my mind again recently – helped along by email correspondence from Gillian Bulmer, who owns orchards at Little Breinton, Hereford and by a recent letter to the Hereford Times by Chris Fairs, formerly of Bulmers cider and an expert on orchard tree management.
The issue is one I’ve raised many times before – though it is often difficult to get the concept across, especially to the media, who are usually far more interested in stories about mistletoe rarity, not abundance. Even the conservation lobby seem to find it hard to grasp sometimes. Very odd.
Yes, mistletoe is rare across much of the country, and yes, mistletoe is good for biodiversity, supporting several other species. And yes it is a traditional plant to grow, with much cultural significance. So, for all those reasons, it is a GOOD plant to have, and even encourage, in areas where naturally rare.
BUT here in its core climatic area (Herefs, Worcs, Gloucs (Severn Vale), Gwent (borders) and Somerset) it grows in huge abundance. And where it is in neglected apple orchards (a favourite habitat and host) it will run amok, taking over each branch of the tree.
General mistletoe management in many older orchards has now ceased, or is much reduced, with often only some fairly random harvesting for Christmas. That harvesting tends to only take some of the berried female plants anyway, so it usually leaves well over half (the male plants and remaining female plants) the mistletoe on the trees intact. Harvesting is notmanagement.
Plus there is evidence (observations only usually, few hard data) that mistletoe is spreading faster than it used to – mostly noticed in areas where it is usually scarce, but also possibly in its core climatic area too (more difficult to measure here though).
Why is too much mistletoe a problem – surely it’s only a hemi-parasite? Well yes, it is fairly harmless in small quantities. But every branch it grows on is tricked, by the mistletoe, into supporting it, the mistletoe, rather than the tree. And so if it is on every branch that tree is in trouble (as is the mistletoe of course!). The problem is compounded by mistletoe’s greed for water – it will transpire water from the tree’s roots freely, all year round, meaning the tree’s leaves are thirstier than they should be in summer and very stressed in prolonged dry weather (see Mistletoe Diary entry here for more info). And then there’s wind-blow of course (eg see the Mistletoe Diary entry below this one for examples). So some mistletoe good, loadsa mistletoe bad.
(For some general background on mistletoe rarity, management, distribution issues etc have a look at the various Mistletoe Matters Information Sheets here or here).
This is, obviously, a problem that needs to be addressed, and must be a key part of any orchard management strategy in this area. But it is difficult to get ‘authorities’ to take it seriously – largely, in my view, because there are no hard data on the problem. No-one has attempted to quantify it, and without statistics the problem doesn’t exist in any formal strategies.
One attempt to rectify this is the Mistletoe League Project I set up a couple of years ago. This aimed to gather management information over several seasons, anticipating slow take-up. And indeed participation has, so far, been limited. I obviously need to do rather more promotion of it next winter, and perhaps simplify the data entry forms to make it more attractive.
But I thought it would be worth posting some graphics of preliminary results up here on the Mistletoe Diary, for the record, and to help inform discussions.
The following is just a brief slide show of some results. Do bear in mind that some of these stats arise from samples of less than 50 respondents (some less than 10), and are geographically spread, so this is not, yet, an analysis of the situation of most orchards in mistletoe’s core area, just a brief snapshot of very incomplete data, and not scientifically valid:
(NB the two differing ‘is there more than there used to be?’ charts are from two different sections of the project – one from the fruit trees in orchards section and one from the fruit trees in gardens section)
There are some new initiatives in the pipeline that might help with mistletoe management, not least the developing (but not yet fully formed) Three Counties Orchard Project which is promoting conservation and management of orchards across Herefordshire, Worcestershire and Gloucestershire. Mistletoe management must be a factor in that.
But even projects like that are short-lived, as their funding only lasts a few years. The mistletoe and orchard problem is here to stay, and needs long-term strategy.
The new mistletoe planting season is here, and we’ve been out harvesting berries for planting projects, grow-kits and just to see how they’re looking this season. Effects of the recent wind and rain are obvious in many of the older mistletoe-laden orchards, with several trees down, complete with mistletoe. Will post some pics of those in due course…
Today I just wanted to post some pictures of aberrant berries. Mistletoe normally has such perfectly-formed spherical berries, each with a single seed, but sometimes the berries fuse in growth, creating monster berries, distorted laterally, and containing several seeds.
One of the plants I was looking at at the weekend had lots of these, perhaps indicating some physiological problem in ovary development, or maybe even genetic disposition, that causes merging (or perhaps splitting, it could happen both ways).
Despite the fusing you can still spot how many berries this should be – as the floral structure leaves a scar on the top of each berry. The big rugby-ball berries in these pictures have 3 scars – so they are three berries in one.
. Commercial break – want to grow mistletoe?
Give the plant that grows kisses for Valentine’s Day!
Studies of European mistletoe’s host preferences often show distinct preferences for particular varieties, or cultivars, within a tree species – so that some varieties of Apple tree are more susceptible than others, as are some varieties of Lime tree, Poplar tree etc.
Demonstrating this convincingly on the ground is difficult – as you generally need a lot of data for lots of trees.
But on Christmas Day this year I suddenly found the perfect demo virtually on our doorstep! And wondered why I’d never noticed it before…
Some background: We live on the edge of Stonehouse, not far from the old Standish Hospital, a rural former NHS hospital now standing empty and decaying in its own grounds – which are a mini-arboretum, with many splendid exotic mature trees. The driveway up to the site has an avenue of relatively young (maybe 30-40 years old) ornamental maples.
Now, we’ve been here over 14 years now, and have walked that drive regularly, as there’s a bridleway route though the site. And over those years we’ve watched as mistletoe has established in those maples, colonising from existing mistletoe colonies in the remnant apple orchards nearby (there’s an old orchard at both ends of the drive) and from mistletoe in nearby poplars.
The revelation: The mistletoe in the maples is now fairly well established – and on Christmas Day afternoon, as we wandered up the hospital drive and back in an effort to walk off some lunch, I was idly assessing the mistletoe in each tree (as one does) – and suddenly realised that… every other tree in each side of the avenue was mistletoe-free. And the mistletoe-free trees were never opposite across the avenue either. So, if plotted on a map the mistletoe trees would be a zig zag pattern along the drive.
And why would that be? Well, these maple trees are two varieties – one a red-leaved one and one a green-leaved one – and they are planted in an alternating pattern. So… the mistletoe, which we’ve witnessed developing over the last 14 years, is only colonising one of the maple varieties – not the other. Which one? Well I think it is the red-leaved one – but will have to wait until spring for confirmation. The aerial photo on the right, when compared to the mistletoe pattern we’ve seen (we checked it again today), seems to confirm red though.
So, there you have it – mistletoe colonising one variety of a tree but not another closely related one – despite having decades to do it in and the trees being right next to each other. I’m just slightly embarrassed that I’ve only just noticed!
Monty’s at it again! His annual mistletoe misinformation project is reduced to one small paragraph this year, published as usual in that bastion of misinformation, the Daily Mail. For comment on one of his longer previous efforts have a look at the the Mistletoe Diary for Dec 15th last winter.
Here’s the new article line by line – with my comments
MONTY’S PLANT OF THE WEEK (Daily Mail 28th Dec)
Mistletoe (Viscum album) “Mistletoe is a parasite.” Almost correct – mistletoe is a hemi-parasite, as it produces its own metabolites through photosynthesis, just like non-parasites.
“The seed is deposited on the bark of a host tree and puts its root into the branch, tapping into its nutrients.” Yes the seed is deposited on the tree’s bark but it doesn’t have ‘roots’ and doesn’t grow ‘into’ the branch – it just penetrates the bark and make the tree’s growth cells grow around it. The only nutrients it takes are from the tree’s xylem system, which is just water and minerals from the soil, not the tree’s own metabolites.
“As the mistletoe grows outwards its roots are growing inwards.” See comments above – mistletoe does not have roots – and does NOT grow inwards – it makes the host grow outwards around it… (and so creates an illusion that it grows inwards – which is a remarkable phenomenon and surely worth mentioning Monty? ).
“Eventually these block the tree’s nutrient supply and the branch dies, killing its parasite with it.” No (see comments above) – though the branch and tree will be much stressed by the mistletoe and too many mistletoes will hasten tree death. For more on the actual mechanisms Monty might try actually reading it up – he could start with some of the info I reviewed here recently on mistletoe and tree mortality – it’s absolutely fascinating stuff and, again, surely worth covering truthfully Monty??
“Mistletoe loves apples, hawthorn and poplar, but no one knows why it grows in some places and not others, although air quality and humidity seem to be important, as does the migration pattern of birds such as blackcaps that excrete the seed onto suitable branches.” Where to start with this one?? Yes the tree list is accurate, but reasons why it grows where it grows are fairly well understood (though obviously not by Monty) and have nothing to do with air quality (is he getting it confused with lichens???) and whilst blackcaps have a role, their winter role in Britain is only recent, in the last few decades, so is most definitely NOT the reason for mistletoe’s established distribution.
And blackcaps wipe the berry – they don’t excrete it. That might seem a minor point but it’s not – it is fundamentally important to how new winter populations of blackcaps might be gradually changing mistletoe distribution – perhaps the most fascinating mistletoe fact of the moment – which is extremely newsworthy and gardening-relevant – though, sadly, it seems to have passed by Monty entirely.
As I said last year, though not in these words, how does he gets paid for this tripe?
If it was written by a non-specialist it would be forgivable – but such inaccurate info from a ‘gardening expert’ is not, in my view, acceptable. .
Commercial break – if you want some accurate information on mistletoe…