Healing The Landscape

 Being custodian of a Grade 1 listed landscape brings with it many responsibilities, not least among these, the challenges instigated by the pathogens and predators of the plants found within. Add to these, the difficulties caused by increasing extremes of climate, flooding, drought and, until the last two year blip, mild damp winters, and we begin to recognise the problems inherent in holding the balance of an imposed ecology on the land.  In my early days gardening here at Shugborough, our main concerns in this area were dealing with honey fungus, blackspot and greenfly/blackfly infestations, all, in those reckless days of unawareness,  remedied by a spray or drench from the chemical store. More recently like many gardens countrywide, we’ve been hit by a growing number of "new" pests and diseases, Phytophthora Ramorum, Pseudomonas and Cameraria ohridella (Horse-chestnut leaf miner) to name but a few.  

Phytophthora ramorum infected Rhododendron

 The discovery of Phytophthora Ramorum (more commonly termed Sudden Oak Death) on a mature Beech tree along the main drive 4 years ago and the steps taken to contain it, brought me into contact with a whole new array of industry professionals. Representatives from the National Trust, Forest Research and DEFRA (now FERA)  amongst others all imparting their own informed take on what is rapidly becoming a worst case scenario for gardeners and landowners countrywide. Through the knowledge gleaned from these experts and adding this to my own perception of our landscape (19 years of hand and mind cultivating the soil here) I realised a new strategy was needed to remedy the impact of such assailants. It began to become clear that there was a sickness in the landscape, something was amiss, enabling the sudden rise in the success of these pathogens, and as countrywide more plants were being added to the susceptible list on an almost daily basis, it was obvious something had to change.

Extensive Phytophthora bleeds on a mature Beech

 My first thoughts were directed toward the recommended containment process for outbreaks of Phytophthora Ramorum which entailed the cutting back and burning of infected plants and any other susceptible species within a 5 metre radius of the initial infection. With Rhododendron ponticum recognised as its main host, the evergreen screen either side of our main drive had to be removed. This seemed like, and by many was perceived, as anti-gardening although its only intention was the prevention of the disease spreading and protecting the greater environment. It gave me a reputation as a "slash and burn" gardener and a “hater” of Rhododendrons, a label I know many in the same position have been given. Interestingly, I and a robin which accompanied me in this “exotic ” removal during that first winter found there was no life at all in the leaf litter beneath the expanse of this shrub’s cover, the ground below was significantly dead.

Phytophthora testing kits showing 3 negative results.

 Obviously the burning process had negative climatic implications, releasing more CO2, the main greenhouse gas into the atmosphere, and I began to look for alternatives to this strategy. Spending days off travelling the length and breadth of the country to study with the Ancient Tree Hunt project made me stop looking at individual plants and start looking at a plants more immediate environment particularly the micro-ecologies that successfully sustained our veteran trees. The majority of these seemed to thrive in areas which did not have an intensive horticultural regime, but were rather left in a more natural environment. It was here that I learned of the importance of the Mycorrhizal communities that reside within the soil, and without which,somewhere near  90% of the planet’s plants would struggle to take up nutrients.

Mycorrhizal colonisation on Pine roots (pic courtesy PlantWorks)

Magnification of mycorrhizal filaments (pic courtesy PlantWorks)

 Mycorrhizal fungi live in a symbiotic relationship with plants, breaking down and making available nutrients from the soil in exchange for plant sugars formed through photosynthesis. The colonization of Mycorrhizae on a plants roots brings other benefits as its vast but largely invisible surface area allows increased absorption of water and also has a protective quality giving less scope for soil-borne pathogens to harvest the plants foodstore. Another distinct benefit of mycorrhizal communities in the rhizosphere (rootzone) is that they hold the greenhouse gas, carbon dioxide, in the soil. Take away these beneficial fungi and the plant becomes stressed, more inclined to become sick through malnourishment and consequently more easily succumbing to predation by pathogens. My eureka moment came courtesy of Ted Green who looks after Windsor Forest who laid the blame for the explosion of Phytophthoras squarely at my door, or the door of gardeners generally, and here’s one reason why:

  Horse manure has always been perceived as one of the best fertilisers for the garden and in the gardening tradition this has been the only manure really useable direct from source. The previous head gardener owned 3 horses so we were self sufficient in the stuff, regularly digging it through the beds to add nourishment or below new plantings to retain moisture in our sandy, free-draining, and therefore very susceptible to drought, soil. After the discovery of Phytophthora on the estate, plant movements were restricted to prevent further contamination and this meant the annual mulching of beds and borders from the leaf-mould pile in the woods had to stop. Prior to the outbreak, each years autumn leaf fall was raked up, transported to a pile in the woods and left to compost to become next years nutritionally beneficial weed suppressing mulch. The suspension of this process meant the beds and borders were beginning to use up their nutrient content, so even more horse manure, procured from a neighbouring stableyard was used.  Little did we know what we were doing.  Horses are regularly innoculated against worm infestation through a treatment that uses the chemical Ivormectin. This constituent passes through the horse and is present in its dung which when applied to a garden has the effect of killing off Mycorrhizae (as well as the invertebrates that break down animal dung). No wonder then, our plants were getting sick, I’m told that if stacked for 4 years the ivormectin breaks down, so I tell people 5 years preferring to err on the side of safety and interestingly it is probably mycorrhizae that break this chemical down. Another beneficial quality of the presence of healthy Mycorrhizae communities in the soil is that it prevents nutrient leach, (nutrients washed away through heavy rain or flooding) and as about a third of our garden is prone to floods, I realized that the landscape I maintained was dying and an urgent remedy was needed.

Summer Floods below the Doric Temple - Shugborough

 My first reaction was to reduce any chemical use in the garden environment. Now Roundup (glyphosate) is the only chemical used, and specifically only for footpaths, spot treating bindweed and injecting Japanese Knotweed. Being a broad spectrum herbicide, ie non selective, it is used carefully and thoughtfully.  Glyphosate works by interfering with the creation of proteins needed for growth within its target plant. It does this by inhibiting a specific enzyme called EPSP synthase by blocking the shikimic acid pathway. This pathway,found only in algae, higher plants, bacteria and fungi, is the reason almost all plants succumb to this herbicide’s destructive power. However, it seems amongst the garden community there is a commonly held myth that it becomes inert when it comes in contact with the soil. This can hardly be true if we think of the prevalence (in healthy landscapes) of  soil-borne mycorhizae. It is likely that this too is destroyed with the chemical’s broad range, and is surely another reason for our gardens becoming more sick. Without the beneficial role of mycorhizae to keep pathogens in check it seems our gardens have become breeding grounds for disease. In the past we have all sought to exhibit the perfect plantings, displaying our specimens with not a weed in sight, and with the steady decrease in available labour in our larger gardens, many of us have succeeded in enabling this desired aesthetic through the application of chemicals. My own understanding of ivormectin and glyphosate has halted this approach at Shugborough, where a new direction, formed through witnessing this very apparent and destructive evidence,  is one pointed toward “healing the landscape”. Now, If roses have black spot, so be it, the same with greenfly/blackfly although last year we did notice a larger population of ladybird larvae, a natural predator for these.

Secondary pathogens colonise following Pseudomonas infection.

 I began to think about the effects artificial fertilisers could have,  another potential source of adverse reactions through their disruption of the "nature" in the soil. Spending evenings poring through scientific papers gave a greater awareness and understanding of the role of mycorrhizae and the ways in which the circumstances in which they thrive might be replenished as by now, it was apparent to me, this was the most important plant- life in the garden. Even after the removal of  host plants, Phytophthora remains present in the ground in the form of chlamydospores. How long these last is unknown but they can certainly allow reinfection to occur, so the prime objective came to be the creation of a nutrient source that would feed plants, that would be beneficial in encouraging mycorrhizal presence, giving plants greater defence against pathogens, and one  that would negate the need for chemical applications. Ideally this would mimic that equilibrium that allows nature’s biodiversity to flourish and stabilize in landscapes that appear healthier when untouched (relatively speaking) by the human hand. This resulted in a plan to introduce plants to replace those that had failed through disease, that would cope with the site’s inherent conditions, (very sandy soil, liable to flood and drought) and thus need less in the way of pampering.

Post-flood dieback on Rhododendron

With no available nutrients to feed the garden’s remaining stock, I began to search for material we could import, something that would not change the inherent acidity of our soil and one that was guaranteed pathogen free (PAS100 accredited). This proved harder than expected and due to cost the idea was soon abandoned.  Thoughts then passed to the possibility of using woodchips as a weed suppressing mulch, but as all of ours were fresh this would have stressed the plants further as fresh woodchips leach nitrogen from the soil. What we needed was a faster breakdown of woodchips. This also coincided with a need to recycle other waste produced from the gardens which without a true composting system we burned or exported as waste. We began to look at composting systems elsewhere and saw variations of the same systems everywhere. Without any disease present in the plant material these "bay systems" probably would have sufficed, although being fairly labour intensive and usually once constructed are immovable structures. Without a practical place to site such an operation other options were needed.

After talking through recycling initiatives elsewhere within the National Trust I was introduced to Tidy Planet and their in-vessel compost machine “the Rocket”. Used elsewhere to recycle food waste and producing fantastic compost in around 2 weeks could it be used to process our diseased and garden waste? It turned out recycling garden waste was the original idea behind the machines design so I set about working on a project brief to convince my managers the initial investment was worthwhile. Whilst the system ticked all of the “green” initiatives now thankfully ensconced in the strategic vision of Staffordshire County Council, I was also able to guarantee if the plan did not work the machine could go to a school, college, university and recycle their food waste. This was perhaps the winning point as in a time of budgetary restraint, I was asked for a business plan. The ball was rolling.
The arrival of Tidy Planet's Rocket A1200

Success for the project brief came in the shape of the Accelerated Compost Rocket A1200 the biggest of the Tidy planet range. The delight seeing it on the back of the lorry quickly turned into a great nervousness as we unloaded it into the end-greenhouse shed, was it going to fit?  With an inch to spare and a huge sigh of relief, it just made it and we could start the process of recycling and the creation of our own compost. The machine is an in-vessel composter where organic materials (in our case woodchip, shredded garden waste and uncooked restaurant waste) are fed into a drum which has an internal auger mechanism that  turns and agitates the material to enable aeration.  The computer controlled internal environment ensures optimum conditions are created for the breakdown of our ingredients and an extractor fan prevents the air inside becoming too moist whilst the system incorporates heat blankets that kick in if the temperature drops below a certain level. Maintaining  specific temperatures ensures the pathogens present in our woodchip are destroyed whilst allowing beneficial microbial activity to thrive, and housing the machine indoors means the machine can keep processing even during extremely cold weather.

Tidy Planet's Rocket A1200 in situ.

 It took a mere two weeks for us to start producing compost, a few teething problems early on were merely down to creating the right mix of ingredients at the input end and before long we were producing about ten dustbins full of  fantastic quality compost a week. The machine’s success has been evidenced by attracting visitors from Sweden, Finland and the Netherlands who came to witness the process and resultant material.  More locally we recently received a highly commended award and a special prize for Sustainable Tourism from Stafford Borough Council for what is still a developing project.

More recent research has led to a decision to trial input of other organic ingredients into our  mix enhancing the potential for habitat creation  suitable to host mycorrhizal communities and  improving its usefulness as a soil ameliorant. In theory these additives will further increase an already beneficial process, and as I write, opportunities are emerging for us to link in with other organisations operating similar schemes worldwide. Through sharing our results, it is hoped we can produce an example of a practical-based strategy much needed in what is a global quest to find ways to remedy what are immediate and very apparent threats to the health of our environment.

To be continued…

Special Thanks for sharing expertise to: Dr Anna Brown (Forest Research), Kath Owen (The Woodland Trust), Ian Wright (National Trust Lead on Phytophthora), Ted Green (Windsor Forest), Brian Muelaner (National Trust Ancient Tree Advisor) Steve Burrows & Steve Potter (Staffordshire County Council), Simon Webb ( Tidy Planet), Graham Lee & Alex Lickley (FERA), Mark Mackie (PlantWorks UK) The Manchester and The Wolverhampton National Trust Volunteer Groups, The Shugborough Garden and Estate Teams and my employers (Staffordshire County Council) for their belief in the project.