Category Archives: Bees

Pollinator biodiversity and why it’s important: a new review just published – download it for free

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In a new review paper that’s just been published in the Annual Review of Ecology, Evolution and Systematics I have looked at the question of just how diverse the pollinators are, and why pollinator biodiversity is ecologically important and therefore worthy of conservation.  I’ve taken a deep time and wide space approach to this, starting with what the fossil record tells us about when animal pollination evolved and the types of organisms that acted as pollinators in the past (the answer may surprise you if you’re unfamiliar with the recent paleontological literature on this topic).  Some of the most prominent biogeographical patterns have been highlighted, and I have tried to estimate the global diversity of currently known pollinators.  A conclusion is that as many as 1 in 10 described animal species may act as pollen vectors.

As well as this descriptive part of the review I’ve summarised some recent literature on why pollinator diversity matters, and how losing that diversity can affect fruit and seed set in natural and agricultural contexts.  Extinction of pollinator species locally, regionally, and globally should concern us all.

Although I was initially a little worried that the review was too broad and unfocused, having re-read it I’m pleased that I decided to approach the topic in this way.  The research literature, public policy, and conservation efforts are currently moving at such a fast pace that I think it’s a good time to pause and look at the bigger picture of what “Saving the Pollinators” actually means and why it’s so important.  I hope you agree and I’d be happy to receive feedback.

You can download a PDF of the review entitled Pollinator Diversity: Distribution, Ecological Function, and Conservation by following that link.

Pollination ecologists should also note that in this same volume of Annual Review of Ecology, Evolution and Systematics there’s a review by Spencer Barrett and Lawrence Harder called The Ecology of Mating and Its Evolutionary Consequences in Seed Plants.  If you contact those authors I’m sure they’d let you have a copy.

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Filed under Apocynaceae, Bees, Biodiversity, Biogeography, Birds, Butterflies, Climate change, Ecosystem services, Evolution, Honey bees, Hoverflies, IPBES, Macroecology, Mammals, Moths, Mutualism, Neonicotinoids, Pollination, Urban biodiversity, Wasps

The Buzz Club: citizen scientists protecting pollinators

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This is a guest post by Charlie Dance who is Development Officer at The Buzz Club.


It’s hard to over-stress the importance of pollinators. Not only do they play an indispensable role in global food security, they’re also essential in maintaining the diversity of plant species in natural habitats, thus supporting nature as a whole. The UK is home to thousands of different pollinators including bees, wasps and hoverflies. However, while many of these species seem to be declining or disappearing, we know surprisingly little about the majority of them. Why are some disappearing, and how quickly is it happening? What can we do to help? How can we turn our gardens into pollinator havens? It was to help answer questions like these that the Buzz Club was founded in 2015.

Run by volunteers at the University of Sussex, The Buzz Club is a citizen-science charity using the power of the public to provide important data on pollinators. We run a variety of nationwide surveys and experiments suitable for all ages and ideal for wildlife and gardening enthusiasts. Furthermore, we provide information about how to make our urban landscapes more pollinator friendly.

For more information and for a list of current projects, please visit our website: http://thebuzzclub.uk/

As a membership-based organisation, we rely on the small donation of £2 per month from members, all of which goes directly towards running the charity. Not only do new members receive a complementary welcome pack containing a specially designed seed mix, bee identification chart, pollinator-friendly gardening guide, magnifying lens and stickers (see photo below), they also get to learn more about pollinators whilst helping to generate useful data that can be used in our projects.

We believe that with your help we can find out how best to conserve bees and other pollinators. Our ultimate goal is to ensure that we look after insects, giving them and us a future.

Join the Buzz Club here: https://alumni.sussex.ac.uk/buzzclub

Facebook: http://www.facebook.com/TheBuzzClubUK

Twitter: http://www.twitter.com/The_Buzz_Club


From Jeff:  if citizen science is your thing, don’t forget that the Ivy Pollinators project will run again this year: https://jeffollerton.wordpress.com/2016/10/11/ivy-pollinators-citizen-science-project/

 

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6000 scientists can’t be wrong: the International Botanical Congress 2017

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A late afternoon flight from Heathrow got me to Beijing International Airport just in time for me to enjoy a nine hour delay in my connecting flight to Shenzhen in southern China.  I finally arrived at my hotel at 2:15am, exhausted and sweaty in the 30 degree night time heat.  The one consolation is the the hotel was short of rooms so upgraded me to a suite the size of a small city, with a shower like a tropical rainstorm.  Perfect to wash off the dirt of travelling before collapsing into bed.

Why am I here and why is the hotel short of rooms?  Because 6000 scientists have descended on Shenzhen for the 19th International Botanical Congress (IBC).  The IBC is a six-yearly event that rotates around the world; I attended in 1999 in St Louis and 2005 in Vienna, but missed Melbourne in 2011.  At this IBC I’m giving two talks, one at the beginning and one at the end of the conference.  More on that later in the week.

Six thousand botanists need a big conference venue and this morning, after a late breakfast, I strolled up to the convention centre where it’s being held.  It’s enormous, the scale of the thing is overwhelming.  I wandered around whilst they were getting ready for registration opening this afternoon and took some images on my phone.

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There are some fabulous displays of living plants, including this one at the main entrance:

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These are attracting pollinators: in 10 minutes I counted lots of honey bees, one butterfly, at least two species of wasps, and a large carpenter bee (Xylocopa sp.) visiting flowers.  I only managed to photograph the first two though:

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On the way back to my hotel I gatecrashed an international turtle expo.  Who knew turtles were such a big thing in China….?

OK, that’s all for now: I have to head back to the convention centre to register, so I’ll leave you with the view I’m seeing from where I’m writing this.  Shenzhen is quite a place and I’ll write more about it later in the week:

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Plant-pollinator networks, the time dimension, and conservation: a new study just published

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After rather a long gestation period, involving much re-analysis and rewriting, we’ve finally published Paolo Biella’s research from his Master’s thesis.  It’s a really neat plant-pollinator network study from mid-elevation grasslands in Italy’s Northern Apennine.  In it we have considered the way in which such networks could be analysed in relation to plant phenology (i.e. the timing of when they flower) rather than arbitrary time slices (e.g. months, weeks).  We have also discussed how this approach may inform conservation strategies in grasslands such as these.  The full citation with a link is:

Biella, P., Ollerton, J., Barcella, M. & Assini, S. (2017) Network analysis of phenological units to detect important species in plant-pollinator assemblages: can it inform conservation strategies?  Community Ecology 18: 1-10 

I’m happy to send a PDF to anyone who is interested in seeing the full study.

Here’s the abstract:

Conservation of species is often focused either only on those that are endangered, or on maximising the number recorded on species lists. However, species share space and time with others, thus interacting and building frameworks of relationships that can be unravelled by community-level network analysis. It is these relationships that ultimately drive ecosystem function via the transfer of energy and nutrients. However interactions are rarely considered in conservation planning. Network analysis can be used to detect key species (“hubs”) that play an important role in cohesiveness of networks. We applied this approach to plant-pollinator communities on two montane Northern Apennine grasslands, paying special attention to the modules and the identity of hubs. We performed season-wide sampling and then focused the network analyses on time units consistent with plant phenology. After testing for significance of modules, only some modules were found to be significantly segregated from others. Thus, networks were organized around a structured core of modules with a set of companion species that were not organized into compartments. Using a network approach we obtained a list of important plant and pollinator species, including three Network Hubs of utmost importance, and other hubs of particular biogeographical interest. By having a lot of links and high partner diversity, hubs should convey stability to networks. Due to their role in the networks, taking into account such key species when considering the management of sites could help to preserve the greatest number of interactions and thus support many other species.

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A new pollinator for our garden: the Ashy Mining Bee

Today I’ve been cracking on with the refurbishment of the old summer house at the back of the garden that previous owners have let fall into rotten disrepair, whilst Karin attends a conference in London.  The renovation has been a slow job, due to lack of time, but a lot of fun, and a good excuse to play with power tools.  In between sawing and drilling, however, I’ve been keeping an eye out for bees and other flower visitors and was delighted to spot a new species for the garden – the Ashy Mining Bee (Andrena cineraria).  It’s a beautiful and distinctive insect that I know from other sites in Northampton, but had not recorded here previously.  The record has been submitted to the BWARS recording scheme for this species.

Do look out for this bee, it’s difficult to confuse it with anything else (which is rare in Andrena….)  Here’s a few photographs of a female collecting pollen from a cultivated rose, that I took with my phone:

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Ashy Mining Bee 2017-06-17 10.56.10

 

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Saved by a bee: a true story, with reflections and photos from PopBio2017

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The blog has been a bit quiet of late, due to a lot of traveling on my part, starting with field work in Tenerife, then a weekend away with friends on the Isle of Wight, followed by the topic of this post: PopBio2017 – the 30th Conference of the Plant Population Biology Section of the Ecological Society of Germany, Austria and Switzerland in Halle, Germany.  And I’d like to begin with a story….

The organisers of PopBio2017 had invited me to be one of five keynote speakers at the conference and I was due to deliver a talk on “The macroecology of wind and animal pollination” first thing (09:00) on Thursday morning.  So the night before I duly set my phone’s alarm for 07:00, thinking I’d have enough time to get ready, have breakfast, then take the tram to the venue (a 15 minute ride/walk).

It was a very hot night and I left the windows open, but my mind was restless with thoughts of how to deliver the talk most effectively.  So I kept waking up during the night, and actually slept through the alarm.  The next thing I know it is 07:45 and I am being woken up by an urgent buzzing noise….from a bee!

I swear this is true: a bee had flown in through the window, buzzed for a few seconds right in front of my face, and woke me up in time to deliver my talk on pollinators!  It then turned around and flew straight back out of the window.

It actually wasn’t until I’d jumped out of bed and into the shower that I’d woken up sufficiently to appreciate what had happened…and wondered if anyone would actually believe me!  Anyway, I got to the venue with 15 minutes to spare, the talk seemed to go well, and it’s a story I think I’ll enjoy telling for some time to come.

The conference was really fabulous, with some very impressive science on show.  It was a good mix of postdocs, PhD students, and established researchers talking on a diverse range of plant ecology topics, not just “plant population biology” (whatever that really is – there was some discussion on that score).   The organisers had arranged the programme so that the keynotes in each session were followed by shorter talks broadly related to that topic, so I was followed by a series of presentations on pollination biology.  And very good they were too.

Here’s some photos from the week:

A slightly blurry audience waiting for my talk to begin (not as blurry as me after the dash to the venue however…):

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I was fascinated by the coypu that are common in the River Salle which flows through the city of Halle.  They are classed as an invasive species, but are very, very cute:

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Indeed so cute I couldn’t resist taking a selfie…

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Some interesting urban greenery including swales for flood defence:

 

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Wall plants surviving the graffiti:

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Halle’s most famous resident, Handel:

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There’s a Harry Potter feel to some parts of the town:

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The fabulous double-double-spired cathedral:

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There had to be a spiral or two, of course:

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On the Saturday after the talks had finished we took an excursion to the fascinating “Porphyry Hills” dry grasslands – unique western extensions of plant communities and species normally found in the east, including many plants of the steppe:

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These rocky outcrops have become exposed as agricultural ploughing caused the surrounding soil level to drop:

 

Some of the grassland areas have very thin soils with resultant high plant diversity:

 

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Lots in flower, though not as many pollinators as I would have liked:

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On the last evening a couple of us had a private tour of the university’s botanic garden, and well worth a visit it is too:

It was a thirsty conference – “To beer or not to beer….”?

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Finally thanks to the organisers of PopBio2017 for the invitation to speak, and to all of the conference attendees who made it such a special meeting.

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Filed under Bees, Biodiversity, Gardens, Macroecology, Pollination, spirals, Urban biodiversity

Generalist pollination can evolve from more specialised interactions: a new study just published

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There’s a long-standing idea in biology that ecological specialisation is an evolutionary “dead end” from which species can never emerge.  In other words, if a species becomes so adapted to a particular ecological strategy (could be feeding or habitat requirements or how it interacts with other species ) then no amount of natural selection will result in its descendants evolving different strategies, thereby diversifying into new species.  In particular it’s traditionally thought that evolving broader, “generalist” strategies from narrower, “specialised” ones is highly unlikely.

This has been much discussed in the literature on the ecology and evolution of pollination systems, where traditionally this “dead end” scenario has been accepted.  However a small number of case studies have shown that generalised pollination systems can evolve within much more specialised clades, beginning with Scott Armbruster and Bruce Baldwin’s study of Madagascan Dalechampia (Euphorbiaceae), published in Nature in 1998.

To this limited body of examples we can now add another case study: in the genus Miconia (Melastomataceae), generalist nectar/pollen rewarding strategies can evolve within a clade of plants that predominantly uses a more specialised, buzz-pollinated strategy involving just bees.

The work is part of the PhD research of Vinicius de Brito who is one of the researchers I was privileged to do some field work with in Brazil when I was there in 2013 – see my post: “It’s called rainforest for a reason, right?  Brazil Diary 6“.  Vini is the guy on the left of the photo accompanying this post.  Here’s the citation and a link:

de Brito, V.L.G., Rech, A.R., Ollerton, J., Sazima, M. (2017) Nectar production, reproductive success and the evolution of generalised pollination within a specialised pollen-rewarding plant family: a case study using Miconia theizans. Plant Systematics and Evolution doi:10.1007/s00606-017-1405-z 

Here’s the abstract:

Generalist plant–pollinator interactions are prevalent in nature. Here, we untangle the role of nectar production in the visitation and pollen release/deposition in Miconia theizans, a nectar-rewarding plant within the specialised pollen-rewarding plant family Melastomataceae. We described the visitation rate, nectar dynamics and pollen release from the poricidal anthers and deposition onto stigmas during flower anthesis. Afterwards, we used a linear mixed model selection approach to understand the relationship between pollen and nectar availability and insect visitation rate and the relationship between visitation rate and reproductive success. Miconia theizans was visited by 86 insect species, including buzzing and non-buzzing bees, wasps, flies, hoverflies, ants, beetles, hemipterans, cockroaches and butterflies. The nectar produced explained the visitation rate, and the pollen release from the anthers was best explained by the visitation rate of pollinivorous species. However, the visitation rates could not predict pollen deposition onto stigmas. Nectar production may explain the high insect diversity and led to an increase in reproductive success, even with unpredictable pollen deposition, indicating the adaptive value of a generalised pollination system.

As always, I’m happy to send a PDF to anyone who wants a copy, just drop me an email.

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British cuckoo bees – an aide-mémoire

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The British bee season is well underway with lots of reports on social media of queen bumblebees (and even workers in the south), and male and female solitary bees (especially early emerging mining bees – Andrena).  In my own garden I’ve already spotted a couple of bumblebee species, plus the Hairy-footed Flower Bee (Anthophora plumipes) and the Grey-patched Mining-bee (Andrena nitida), amongst others.  Running alongside the emergence of these nest-building bees is a whole suite of “cuckoo” or “cleptoparasitic” bees that, as the name suggests, lay their eggs in the nests of other bees, consuming the pollen that has been collected and, usually, the eggs and larvae of the host bee.

The specificity of the interactions between the cuckoos and their hosts varies a lot.  Some are very host specific, such as the bumblebee sub-genus Psythirus that only parasitises other Bombus species.  Others are much broader in their host use, such as the genus Nomada that parasitises five other British bee genera.

Personally I struggle to recall which cuckoo bees interact with which host bees, especially for those with a broader use of hosts, so I thought I would construct an aide-mémoire in the form of an interaction graph using the R package “bipartite”.  I took the information on which cuckoo bees parasitise which hosts from Steven Falk’s recent (and very good) book Field Guide to the Bees of Great Britain and Ireland.  If anyone spots any errors, please let me know!

The bipartite graph is structured such that the hosts (to the left, in black) are ranked from most to least parasitised (in terms of number of cuckoo genera that interact with them).  The cuckoo bees (in grey on the right) go in the reverse order, from most specialised to least specialised.  Note that this set of interactions only applies to Great Britain and Ireland; breadth of host-parasite interactions is wider on the Continent and elsewhere in the world.

Here’s a link to a better quality PDF of the plot that you’re free to use for your own use: Cleptoplot

Here’s the data matrix (Clepto) and here’s the R script if you want to play with it:

> library(bipartite)

#Turns the CSV data file into a data frame and assigns the first column to be the row names

> Clepto2<-data.frame(Clepto, row.names=1)

#Basic plot of the web

> plotweb(Clepto2)

#To turn the plot 90 degrees and centre the image, change spacing and text size, colours, etc.

> plotweb(Clepto2, method=”normal”, text.rot = 90, labsize =1.5, ybig = 0.7, low.y = 0.7, high.y = 0.98, plot.axes = FALSE, y.width.low = 0.05, y.width.high = 0.05, col.high = “lightgrey”, bor.col.interaction=”black”, bor.col.high=”black”, low.spacing=0.03, high.spacing=0.08)

#Note: save the figure as a PDF, much better quality than PNG

#With thanks to Kat Harrold who provided some of the script

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Dispelling the myth that orchid species usually only have a single pollinator

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The idea that members of the plant family Orchidaceae (the orchids) “typically have exclusive relationships with their pollinators“, such that each orchid has only one pollinator, is a persistent one.  Recently I’ve encountered it on horticultural websites (follow that last link), in grant proposals, and on Wikipedia.

The problem is that it’s not true: it’s a myth that is perpetuated by people (often botanists or horticulturalists) who may know a lot about orchids but don’t know as much as they think they know about pollination ecology.

Orchids certainly have some fascinating and often quite intricate floral mechanisms to ensure pollination, but these have not necessarily evolved to attract and exploit just one species of pollinator.  Even in the case of sexually deceptive orchids that fool their (male) pollinating insects into believing that they are mating with a female of the same species, it is sometimes the case that more than one insect species is involved.  For example, in the well studied genus Ophrysflowers are pollinated by a narrow taxonomic range of pollinators, from a single species to up to five closely related species“.  As the authors of that last paper state, this is not the same as the mythological “extreme case of one orchid/one pollinator”.

Likewise different species of orchid bees may pollinate the same orchid flowers as they visit to collect scent compounds; for example in the Brazilian species Dichaea pendula, species from at least two different bee genera act as pollinators (Nunes et al. 2016).

The fact that “one orchid/one pollinator” is a myth is not new knowledge, it’s been widely discussed in the pollination ecology literature for decades.  For example, in our 1996 paper “Generalization in Pollination Systems, and Why it Matters” we showed data from the late 19th/early 20th centuries that clearly indicated a range of specialization in European orchids (follow that link and look at  Figure 3B).  Even earlier than this, in his 1992 paper “Trends in the pollination ecology of the Orchidaceae: evolution and systematics” Raymond Tremblay showed that only about 62% of species for which he could find data had a single pollinator, and that this varied considerably between different subfamilies of Orchidaceae, with some subfamilies being more specialized than others.

More recently, in a chapter in the 2006 book I co-edited with Nick Waser entitled “Geographical Variation in Diversity and Specificity of Pollination Systems” Steve Johnson, Andrew Hingston and myself looked at data from southern African compared to North American and European orchids; here’s the figure from that assessment:

 

Ollerton et al Figure 7 - JPEG

Orchids  are more specialized in southern Africa compared to Europe and North America (as are a number of other plant groups including the asclepiads, which we’re comparing them with here).  But even in southern Africa, only about 65% of the orchids studied have a single pollinator species.  It’s worth pointing out, though, that many of the species included in this analysis, and in Raymond Tremblay’s paper, have been studied only at single sites and often in single years, meaning that we have no idea if there is any spatio-temporal variation in the pollinators a particular orchid species exploits.

Why does this myth persist?  I think it’s for the same reason that myths are retold from generation to generation: they are great stories that fascinate the teller and the audience.  Indeed, orchids are very special plants with some amazing floral and vegetative adaptations, fascinating relationships with fungi, and incredible diversity.  But we don’t have to mythologise their relationships with their pollinators to try to make orchids more special than they already are.

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The Danish for garden is “haven”: five reasons why I love Gardeners’ World

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The latest series of the BBC’s flagship horticulture programme Gardeners’ World started on Friday, heralding its 50th year of broadcast – quite an achievement.  I’ve long been a fan, and a few years ago jumped at the chance to take part in one Science in the Garden special episode with Carol Klein (which I’ve posted about previously).  Since Friday I’ve given some thought as to what I get from the programme and have come up with a list of the main reasons why I love watching it:

1.  At its heart, Gardeners’ World is about the main subject of this blog and of my career: biodiversity.  Specifically the programme is centred on the biological richness of wild plants and the diversity of the horticultural varieties that we have created from them, for food and for ornament.  Spinning off from this is the acknowledgement that, although much of it is not native to Britain, this plant biodiversity (and the way in which we manage it in our gardens) can have important positive benefits for the wildlife of our country, including birds, amphibians and reptiles, and insects such as bees and butterflies.  This is particularly the case in urban settings and I’ve noticed a welcome trend in recent years for Gardeners’ World to include more features about city horticulture.

2.  Gardeners’ World has long championed a more environmentally friendly approach to horticulture, bringing in ideas about using peat-free compost, minimal use of biocides, recycling and upcycling, composting, and growing your own food, long before any of this became fashionable.  Indeed there’s a strong argument to be made that earlier presenters such as the late Geoff Hamilton were responsible for such fashions gaining mainstream exposure, influencing the habits of millions of people in Britain.  That kind of influence should not be under-estimated.

3. Gardeners’ World reminds me of my dad, who died in 1996.  I can recall him watching it back in the 1970s when Percy Thrower was the presenter and my dad had an allotment a short walk from our small terraced cottage house, with its tiny concrete backyard.  Some of my earliest memories of plants and nature relate to that allotment: a huge rambling rose along the fence; a greenhouse made from old window panes, filled with the rich scent of tomatoes; a toad that dad put in that greenhouse to eat the slugs; rainwater tanks hosting little communities of wriggling insect larvae.  After the allotment plots were cleared by the local council and sold for development my dad erected a greenhouse in the backyard, and grew shrubs and bedding in large pots.  In the early 1980s this was joined by a second small greenhouse for my cactus and succulent collection, many of which I still have.  Some of the best stories in Gardeners’ World are as much about people and their relationships with one another and with their gardens, as they are about plants and gardening per se (see also number 5, below).

4.  Despite having watched the programme for many years I still get new things from it.  Each season I gain inspiration for new plants and new ways of working with the garden that Karin and I are developing here in Northampton, which I’ve talked about quite a few time; see for example:  Renovating a front garden…, my post about Scientists and gardens, and the series I did on pollinators in the garden for Pollinator Awareness Week.  Gardeners never stop learning.

5. Being from the north of England I’m intrigued by the linguistic links between that part of our country and Scandinavia, particularly shared words such as “bairn”, and place-name elements such as “holm”.  Karin is Danish and these connections of language are something we often discuss.  Recently she pointed out that the Danish word for garden is “haven”.  Although it’s not pronounced in the English manner that word is probably the best single way of describing how I feel about our garden; it’s a haven from from the outside world, a place of rest and security, contemplation and physical activity, emotionally supporting us, and providing resources and space for the wildlife that uses it.  Although we don’t do much work in the garden during the winter, each year the start of a new season of Gardeners’ World reminds me of the pleasures to come in our own haven.

Of course there are sometimes things that irritate me about the programme: it can be a bit too cosily middle class at times, occasionally the advice offered can be simplistic or inaccurate, and some of the “scientific” trials of plant varieties lack rigour and replication.  Nonetheless, it’s a programme I have grown up with and one that I love to watch.  Happy Anniversary Gardeners’ World, here’s to 50 more years!

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