Dec 222016

PROTREE is using Scots pine as an example to explore how forestry can encourage resilience in our tree populations.

Tackling the tree health problems caused by an ever expanding number of new pests and diseases is not just a matter of being vigilant and responding to outbreaks. Just as vital is the aim of building resilience into our forested landscapes. It is this second approach that has provided the focus of work by RBGE and six other Scottish research institutes involved in the PROTREE project.

In order to reach a wide audience, and in particular young people who will be the next generation of plant health specialists, PROTREE has opted to use the medium of computer games. Getting across the message about genetic diversity and its fundamental role in enabling tree populations to become more resilient is ultimately the challenge that we faced with this game. Working together, the scientists and a team of games designers at Hyper Luminal Games have created CALEDON. The game makes you the manager of your own virtual forest and is targeted primarily at teens and secondary school teachers. Having said that, anyone with an interest in plant health or the environment can learn by playing the game and it has already been used as a teaching aid in the forestry sector.

The game includes an encyclopaedia that helps players develop knowledge and hone their strategy.

The way tree species and pathogens interact with each other and the environment is informed by the real world, and the game is in effect a simple forest simulator. Although it is educational entertainment and not a tool for real-world planning, the game could be used to illustrate how differences in genetic diversity or species composition might affect response to a disease. The player is completely in control of the pace as time is only advanced when all the changes s/he wishes to make and can afford (the game has a financial aspect) have been made. Time is then advanced by five years and in a few seconds all sorts of interactions and random events will play out.

CALEDON has been well recieved at a series of public events in 2016.

The hope for CALEDON is that players of the game learn something about the many threats our trees and forests face and the complexity of creating a sustainable forest landscape. In addition, a sense of the value of genetic diversity should become clear from experience, in-game prompts on good strategy and an encyclopaedia that can be consulted at any time. Ideally the game will introduce some new thinking and perhaps even stimulate a shift in direction for forestry that acknowledges diversity and its important role in tree health.

Educational computer games are an entirely new departure for RBGE, and the process of scientists and games designers working together has been positive. If this first foray into a new medium for communication is successful we can expect to see more games in the future.

Mar 312016
Mary Gibby and Heather McHaffie

Protection of the habitat is a perhaps the most effective method of conservation of plant diversity, yet this alone cannot guarantee the survival of some of our most threatened species. Changing climate, the introduction of new predators or diseases, and many other factors can affect the survival of a small population. To best achieve success in conservation, knowledge of the plants’ biology, its life cycle and population structure together with information on the reason’s for decline of a population are all essential ingredients for the maintenance of a population. A strategy for conservation for one species may differ considerably from that of another species.

Two fern species have been the subject of conservation programmes by two of our Research Associates, Mary Gibby and Heather McHaffie. What they share in common is the reason for their past decline; both were targets of enthusiastic collectors, especially during the second half of the nineteenth century, when the Victorian fern craze – so-called “Pteridomania” – was at its height. The ferns were sought out for private collections of pressed specimens or for cultivation, often in glazed Wardian cases, to ornament elegant drawing rooms.

Mary Gibby and Heather McHaffie

Mary Gibby – First female Director of Science at RBGE (left)
Heather McHaffie– former Scottish Plants Officer at RBGE

We have good documentary evidence of the decline of the two species, preserved for posterity in the herbarium at RBGE. Although RBGE was founded in 1670, the establishment of the herbarium dates from 1873 when the collections of the Botanical Society of Edinburgh (B.S.E., now the Botanical Society of Scotland) were donated to the Garden.  Amongst the plants collected by members of this august society is small specimen of the Killarney Fern, Trichomanes speciosum, the first record of this plant from Scotland. It was discovered in 1863 by Robert Douglas, the ‘walking postman’ of Arran. His find was confirmed by the Edinburgh naturalist W. B. Simpson, who suggested that Douglas should keep the information secret. Douglas, however, showed the site to George Coombe of Glasgow, who returned and stripped the site almost bare. The annotated herbarium sheet (Figure 1) with two small fronds includes a letter from George Coombe.

Trichomanes speciosum Killarney Fern

Figure 1: Trichomanes speciosum (Killarney Fern)

The decline of Oblong Woodsia, Woodsia ilvensis, is linked closely to the opening up of the railways. A major centre of the distribution of this little plant was the hills around Moffat, in southern Scotland, and fern enthusiasts were so keen to acquire specimens that a trade in the plant grew up for visiting tourists at Moffat station. In a report of a plant hunting trip by a few friends from the B.S.E., they describe after a very long search finding five plants of the Woodsia, four of which they collected, leaving one behind as “an egg in the nest”! Two large pressed whole plants from this expedition are on the sheet in Figure 2.

Woodsia ilvensis Oblong Woodsia

Figure 2: Woodsia ilvensis (Oblong Woodsia)


Both ferns are of conservation concern in the UK, and the Killarney Fern is included in the EU Habitats Directive. In Species Action Plans developed in the 1990s, it was proposed that for both species conservation action through restoration should be considered. Study of the biology of the Killarney Fern has shown that the fern has two distinct and long-lived forms to its life cycle; the normal spore bearing fern (sporophyte) with a creeping rhizome is confined to very humid, shady conditions usually below 50m altitude, whilst the gametophyte generation, with a green filamentous structure that bears the sex organs, thrives in deep crevices, and under very low light conditions. Whilst the distribution of the fern is extremely limited, being confined mostly to a few sites in western Britain and Ireland, the gametophyte is much more widespread, on the north, south east and west coasts of the UK, and the gametophyte populations carry much more genetic diversity that that remaining in the few sporophyte populations. The gametophytes are a living spore-bank that has the potential to give rise to further sporophyte populations under warmer and wetter conditions. Re-introductions have been deemed inappropriate for this species.

There are now fewer than 100 plants of Oblong Woodsia in the UK. One population near Moffat has been seen to decline from c. 25 plants down to only three in the last forty years, and with the exception of a population of over 60 plants in England, many of the Scottish and Welsh populations are limited to less than six plants. It is still unclear why the species continues to decline, and why new plants are failing to establish. Andrew Ensoll has had great success in establishing a very large ex-situ collection at RBGE of the species from spores collected under licence from throughout the species’ range. With the support of Scottish Natural Heritage and Natural England several new populations have been established in areas where the species has been lost, and these continue to be monitored. There has been fairly good survival of these re-introductions, but despite some having been established for 15 years, there is still no evidence of natural regeneration in the wild.

One of the few plants left of Woodsia ilvensis growing wild in Scotland

One of the few plants left of Woodsia ilvensis growing wild in Scotland

The next generation of females in science takes this work forward – Nadia Russell, a PhD student based at the Garden, is carrying out further research on the genetics of the species to see whether genetic rescue is feasible.



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Mar 162016
Photo: Ancient Pollarded Ash near Killin (and the Author)

Photo: Ancient Pollarded Ash near Killin (and the Author)

Archaeological studies have shown that, ‘Biochar’, or at least a similar product, was used by ancient Amazonians to add to the soil to help with their food growing. Today, an advanced form of Biochar is made from the slow charring of waste woody biomass, using a restricted oxygen supply (a process known as pyrolysis). A stable form of carbon is produced and one tonne of carbon locked into biochar, is equivalent to removing three tonnes of atmospheric carbon. Adding it to the soil around trees and food crops, enhances soil nutrition and improves soil structure and drainage – and hence plant growth rates, without the need for further artificial fertilisers.

Biochar has a honeycomb-like microscopic structure, which makes it an ideal habitat for beneficial soil microrganisms, like mycorrhizal fungi. It also aids with the retention of water in soil, reducing irrigation requirements.

Biochar was applied to the soil around ash trees, to assess effects on growth. During the trial many of the trees on the experimental site became infected with Hymenoscyphus fraxineus, leading to Ash Dieback. Surprisingly enough, not a single ash tree treated with the Biochar, showed any signs of the disease, whilst many adjacent trees were badly affected. A PhD study into the potential for use of Biochar to prevent Ash Dieback, has now been commissioned – another potential sprig of hope for the UK’s 126 million ash trees! The link given below takes the reader to a video about the original findings.

Video Outlining Potential for Biochar to Reduce Ash Dieback Infection Rates

Feb 132016

There is renewed optimism for the future of ash trees in the UK, following new research which has identified genetic markers for susceptibility to Ash Dieback caused by Hymenoscyphus fraxineus. For the first ever time in trees, a technique called, “Associative Transcriptomics”, has identified three genetic sequences linked to susceptibility. By identifying potentially resistant trees in the field, we may begin tree breeding programmes using the resistant trees. Resistant trees could then be planted out in areas affected by Ash Dieback, to replace dead and dying trees.

“Association genetics” can quickly and efficiently identify regions of the genome that control traits and provide markers to accelerate breeding by marker-assisted selection. However, as most crops are polyploid (genes in sets of two or more) it is hard to identify the required markers and put together a genome sequence to order those markers. In contrast, “Associative Transcriptomics” – a recently developed technique – uses transcriptome sequencing to identify and score molecular markers representing both gene sequences and gene expression. It then correlates this with trait variation.

fallen ash regrows mums

For anyone wishing to read the technical research paper, here is a link to the published article:

And here is an interactive link to the Forestry Commission map showing where Ash Dieback has been found since first discovered in the UK in 2012 (26% of 10km squares have infected ash).

The above picture shows the resilient nature of ash – vigorous regrowth from the stump of a tree which fell in high winds.

Dec 232015
Ancient ash near Menstrie, Clackmannanshire

Ancient ash near Menstrie, Clackmannanshire

Ash dieback, caused by Hymenoscyphus fraxineus (aka Chalara) infection was first recorded in the UK in 2012. Symptoms include blackened or withered leaves, crown dieback and diamond-shaped bark lesions. The disease has been recorded in growing numbers of sites in England, Scotland and Wales, though Northern Ireland hasn’t reported any cases in the wider environment yet. In just three years, about one quarter of all 10km grid squares in the UK, now include infected ash sites. There are an estimated 126 million ash in the UK, some 10.7 million of these being in Scotland. European experience suggests we may lose up to 99% of our ash trees during the progression of the disease.

Interactive map

Those that survive, may be under further threat in the future, as the invasive jewel beetle, Agrilus planipennis (Emerald Ash Borer, or EAB) is working westward and southward from Moscow through Russia, progressing at about 25 miles/year. In North America, some 7 billion ash trees are potentially under threat from EAB, which puts the UK situation into perspective. EAB attacks result in up to 100% mortality, so the prospects are bleak for ash and many associated species in the UK, Europe and North America.

This problem is a direct result of increasing human, animal and plant movements and, coupled with the effects of global warming, is likely to herald a new era where we see ‘traditional’, or long-established landscapes, rapidly transformed through plant and animal species losses.

Scientists are working on various projects to save our ash trees and their associated plants, animals and fungi. Biosecurity has been stepped up a gear, replacement planting programmes are being devised (using species which offer some habitat continuity for associated ash species) and genetic research has included the successful gene mapping of a British ash, a resistant tree from Denmark and the actual fungus, Hymenoscyphus fraxineus.

Six tree breeding methodologies are being explored by Queen Mary, University of London, including GM, hybridisation and back-crossing. All 35 global ash species will be researched, including some from China which show resistance to the disease. Conventional breeding would take many decades, and GM would undoubtedly be quicker. There is however, a public perception that GM is problematic and research carried out by Oxford University (N=1400) suggests highest public acceptability is for breeding native tolerant ash, using accelerated breeding to breed native tolerant ash, and cross-breeding of native ash with non-native ash.

RBGE has provided the Forestry Commission and Queen Mary’s with genetic material from the Living Collection, for use in their research work on ash dieback.

For further information about ash dieback, visit where the ‘useful links’ section provides information on the likely Scottish/UK ecological impacts, timber treatment and  movement legislation, and chemical treatment test results.

Dec 162015
Wild celery seedlings in the poly tunnel at the Botanics in spring 2015.

Wild celery seedlings in the poly tunnel at the Botanics in spring 2015.

As 2015 draws to a close we end the third growing season for the Really Wild Veg project. The aim of the project is to explore how domestication has changed crop plants by comparing them with their wild ancestors in growing trials. As in previous years trials have been conducted here at the Botanics, by the Edible Gardening Project team, and at Redhall Walled Garden and Hermitage Vegetable Garden. A newcomer for 2015 has been Glasgow Botanic Gardens. Elizabeth Mittell, a PhD student with the University of Glasgow, is studying brassicas in order to explore the potential of this important group of crops in the context of increasing food demands and the stresses imposed by climate change.

Some of the growth trials at Glasgow Botanic Gardens have fed directly into the nutritional work being carried out by the Rowett Institute of Nutrition and Health as part of the Really Wild Veg project (see below). For more on Elizabeth’s work on brassicas check out her blog.

Brassica plots at Glasgow Botanic Gardens in summer 2015.

Brassica plots at Glasgow Botanic Gardens in summer 2015.

A particularly fun part of the project this year has been to explore taste preferences with members of the public in blind tastings. In general wild relatives of crops have stronger flavours. What we wanted to know was how people regard these flavours. Tastings at public events seemed an ideal opportunity to both engage a wider audience with the aims of the project and at the same time generate an indication of flavour preferences. To this end a series of blind tastings were conducted and the results are outlined below as the percentage vote for the best flavour:

Crop Circle discussion (panel of 47): Wild Cabbage 55% (26) vs. Cabbage 45% (21)

Crop Circle discussion (panel of 47): Wild Celery 70% (33) vs. Celery 30% (14)

SciMart market (panel of 71): Wild Cabbage 46% (33) vs. Cabbage 54% (38)

SciMart market (panel of 70): Wild Celery 51% (36) vs. Celery 49% (34)

Royal Highland Show (panel of 14): Wild Cabbage 79% (11) vs. Cabbage 7% (1) with 14% (2) undecided

So, in four out of five tests the wild plant gained a majority of votes, although in three of these cases the preference for wild over domesticated was not particularly marked. Despite not being scientifically robust data, these results do hint at a liking for more intense flavours.

Interestingly, a visiting group of students from Queen Margaret University studying for an MSc in Gastronomy also participated in a taste test with wild cabbage and cabbage. One might expect that such a group of highly-tuned palettes would be able to detect differences between the samples. The results below show a clear preference for the wild plant:

QMU student visit (panel of 15): Wild Cabbage 73% (11) vs. Cabbage 27% (4)

Celery trial plots at the Botanics showing wild celery (left), which is clearly less leafy and erect.

The format of the growing trials has remained the same in 2015. Three replicates of each species are grown side by side in blocks to try to ensure that environmental variation is kept to a minimum. The replicates represent different strains as follows: 1. wild type (where possible collected from the wild); 2. heritage variety; and 3. modern F1 hybrid cultivar. Samples of each strain in a trial were sent to the Rowett Institute of Nutrition and Health for analysis of phytochemical content with a focus on compounds linked to prevention of diabetes, cancer and heart disease. In addition, each strain was scored for productivity by weighing a specified portion of the crop. Plant health issues were recorded to see if certain strains display greater resilience and, as noted above, blind tastings were conducted to assess flavour preference.

During 2015 the focus on brassicas and celery has generated relatively few new results for productivity. Brassica trials have been conducted every year and additional data on productivity was not needed. For the celery trials the only data available at the time of writing is presented below. These data are from a sample of eight plants of each of the three strains grown at the Royal Botanic Garden Edinburgh by the Edible Gardening Project. In each case only the above ground parts were weighed:

Wild Celery – 368g, 162g, 178g, 152g, 133g, 130g, 159g, 51g with a total of 1,333g and a mean of 167g

Heritage Celery – 197g, 405g, 155g, 428g, 141g, 49g, 283g, 289g with a total of 1,947g and a mean of 243g

F1 Hybrid Celery – 175g, 197g, 240, 436g, 350g, 147g, 427g, 412g with a total of 2,384g and a mean of 298g

These results fit an expected pattern in which F1 hybrids are most productive and wild ancestors least productive. Domestication is to a large extent driven by a desire to increase productivity so we would expect wild plants to be relatively unproductive. In the case of F1 hybrids the crossing of two genetically distinct strains to create the F1 hybrid is the source of what is known as hybrid vigour. One manifestation of this is increased growth, and this explains why F1 hybrid strains are so commonly available to the home grower.

During 2016 the investigation of edible wild plants as novel crops will move away from Scottish native crop wild ancestors. We plan to grow trials of black nightshade (Solanum nigrum) collected in the UK and from a seedbank in Holland. This species is a weedy member of the potato family that is semi-domesticated in some areas (particularly Africa) and grown as a versatile crop that has edible leaves and fruits. In Scotland it is not native, but we are confident it will grow here as our herbarium has numerous examples of this species collected in Edinburgh and elsewhere in Scotland over the last 100 years or so. Most of these are garden weeds or accidental introductions with imported products. As a result many of the records are from Leith, a major trading port in the past. To start this exciting new project off with some UK origin seeds the Natural History Museum was contacted and has kindly supplied a selection of fruits removed from recently collected herbarium specimens (see below). It will be interesting to see if these seeds are still viable, but if not the Dutch seeds will enable a range of trial plots to be grown so keep your eye out next spring in the area adjacent to the Queen Mother’s Memorial Garden.

Seeds of black nightshade supplied by the Natural History Museum from recent herbarium collections.

Seeds of black nightshade supplied by the Natural History Museum from recent herbarium collections.

Sep 162015
Celery seedling sown on 17th March 2015 as part of the Really Wild Veg growing trials.

Celery seedling sown on 17th March 2015 as part of the Really Wild Veg growing trials.

The wet summer may not have been much fun, but our celery has been loving it. One of the real challenges with growing celery on well-drained soils is keeping it damp enough so that it grows strongly and does not bolt early.

The three trial plots each contained eight plants grown as two rows of four. The harvest on the 26th August gave the following weights:

Wild – 368, 162, 178, 152, 133, 130, 159, 51 making a total of 1,333g with an average weight of 167g

Heritage – 197, 405, 155, 428, 141, 49, 283, 289 making a total of 1,947g with an average weight of 243g

F1 – 175, 197, 240, 436, 350, 147, 427, 412 making a total of 2,384g with an average weight of 298g

No pest or disease damage was noted in any of the plants and the only problem has been that by September a few plants had begun bolting. Interestingly, none of the wild plants have bolted.

Aug 142015

Fraxi_Media_Img_1It may seem an unlikely task but Asylon Theatre have created a beautiful and intensely moving piece of theatre inspired by the devastating ash-dieback disease that is spreading across the country. Currently showing in the Fletcher Building at RBGE at 11am each morning the show is adverstised for age 8+ but I feel that people of all ages, adults as well as children, will enjoy and be moved by this passionate play that combines physical theatre and drama with a story of three generations of woodlanders and one regal ash tree. The story is narrated by a child and this makes it all the more poignant. It is performed by three actors who move around the stage with energy and pitch perfect timing so with minimum props you feel immersed within the ash forest at all seasons and in all weathers. The touching human stories are intertwined in a playful way with the life of the tree, its birth, survival and ultimate death. Humour is added with charming vinettes from a caterpillar who is continually eating dog violets throughout the performance until finally emerging as a butterfly.
A tremendous amount of development has gone into creating this highly professional performance and it deserves to be seen by a much bigger audience. This being the Edinburgh Fringe it is competing with a very large number of mediocre shows but do go and see it, and take your friends and family. You will not be disappointed.

Jul 302015


Here is a list of jobs to do in the garden this month:

Weed regularly to prevent weeds setting seed for next year.

Water copiously if we have a dry spell.

Harvest crops while they are in peak condition.

  • Make preserves such as jams and chutneys or cook and freeze batches of soup or sauce.
  • Dry onions, garlic and shallots for winter storage. Lift and lay them out somewhere well-ventilated and dry for two or three weeks. They can then be stringed, click here to find out how to do this. Any onions that show signs of mould or rot should be eaten straight away because they will not store.


  • Winter hardy salads such as lamb’s lettuce, land cress, winter purslane (Claytonia perfoliata) and winter lettuces
  • Chard, leaf beet and perpetual spinach
  • Spring cabbage
  • Green manures for vacant plots to protect the soil and build fertility. We use winter tares (Vicia sativa) and Phacelia tanacetifolia.

Order onions, garlic, broad beans and peas for autumn sowing.

Feed tomatoes every couple of weeks with a high potassium tomato fertiliser. Remove a proportion of the lower leaves to allow greater air circulation, this discourages disease. Pinch out side-shoots and nip the top out of the plant once four trusses of tomatoes have developed.

Practice good hygiene. Be vigilant; remove dead or diseased plants and foliage quickly to prevent spread the spread of disease.

Erect nets to protect winter crops from hungry pigeons. Be prepared, even if your brassicas are not being attacked now, when winter arrives there is very little else for pigeons to eat so plants are very vulnerable.

Summer prune trained fruit trees such as espaliers, cordons or fans to maintain their shape and productivity. The exact timing depends on how the new growth is developing. Initially new shoots are soft and flexible, through the season they become stiff and woody. Summer pruning should be carried out when the bottom third of the new shoots is stiff and woody. To find out how to summer prune your fruit trees click here.

Prune summer fruiting raspberries once the fruit has been picked. Cut the old canes to ground level; leave the new shoots to fruit next year. For more information on pruning raspberries click here.


Prune raspberries


Feb 012015

Many typical winter tasks can be done in February, such as: preparing the ground for spring seed sowing, planting new fruit trees and bushes and pruning apples, pears and soft fruit.

Annual pruning of trees and bushes aims to encourage well-spaced branches that produce ripe fruit. In addition, pruning helps to maintain the health of the tree or bush by removing dead, diseased, damaged and congested branches. There are lots of good pruning tips on the RHS website.


Pruning fruit trees

It is unlikely that many seeds would prosper if sown outside now. There is always a temptation to rush out and sow seeds early. However seeds sown later into warmer soil tend to catch up with earlier sown seed and have less chance of rotting.

If you have a warm greenhouse or polytunnel it may be possible to sow a range of crops such as radish, beetroot, chard, early carrots, parsnips, cabbages, kale, kohl rabi, hardy salad leaf mixes, rocket, peas and broad beans.

Chillies and tomatoes benefit from an early start. They need a high temperature to germinate so should be sown in a heated propagator or warm windowsill. Other things to sow in heat now include celery, celeriac, onions and leeks.

Many garden centres will now be stocking seed potatoes. Potatoes are tender and should not be planted out until late-March or early-April. Seed potatoes can be encouraged to sprout before planting by placing them in a cool, light place; this is known as ‘chitting’. The ‘chits’ (shoots) develop from ‘eyes’ on the potato, the ‘eyes’ are usually concentrated at one end of the potato. An old egg box is a useful way of arranging the tubers so their ‘eyes’ are upright.

potatoes chitting

Potatoes chitting