Category: Regenerative Planting

A natural Xeriscape
March 23rd, 2018 by Mark Laurence

A problem, or an opportunity for a new landscape paradigm?

 

I was recently working on a tree project in Abu Dhabi when I came across a derelict site which intrigued me with it’s range of exotic self-seeded, non-native plants.  The site was next to the Corniche and sandwiched between the Formal Park, my hotel and Capital Gardens.  It struck me initially as the perfect basis of a xeriscape, as all the plants (mostly trees) were thriving without irrigation.  On closer inspection and identification of the species involved, things got more complex and raised a lot of potentially conflicting thoughts and issues.

A natural Xeriscape

A natural Xeriscape

The site was clearly awaiting redevelopment and the plant invasion was opportunistic.  Nothing that I could identify was native, yet all seemed happy there.  When you see the list, you might understand why.  Amongst the plastic and litter I identified:

  • Prosopis juliflora
  • Ficus benghalensis
  • Eucalyptus glaucescens
  • Conocarpus lancifolius
  • Washingtonia robusta

Of those plants, the P. juliflora was the most robust and when you look at its reputation, that is of no surprise. It was of landscape scale, lush and greener than anything in the adjacent parks.  It’s form, leaf, flowers and seeds are attractive from a landscape perspective.  Yet this is undoubtedly the most controversial plant on this list – some would say alarming.  A Native of arid zones in central and South America, this was, like so many others, introduced into the UAE in the 70’s as a forestry plant.  Lauded as something of a super-crop tree, it is tenacious, vigorous, provids fuelwood and stock-feed in the form of abundant seeds.  The latter, it turned out, were a problem in that they are spread by cattle and are extremely aggressive.  Plants also regenerate rapidly from the roots when cut back and they reputedly produce biochemical inhibitors to suppress competition (allelopathy).  With no natural competitors in the UAE and roots that can descend 50m in search of water, they out-compete native flora, even their cousin, Prosopis cineraria (ghaf tree).

Prosopis juliflora flowers

Prosopis juliflora flowers

P. juliflora has a low, mounding habit, attractive from a landscape point of view.

P. juliflora has a low, mounding habit, attractive from a landscape point of view.

Also on the site were a number of Banyan trees, Ficus benghalensis, which seemed to be growing happily. Another tough survivor, it should be borne in mind that the water table here is likely only a metre or so below ground, although it will have a high saline content.

Ficus benghalensis

Ficus benghalensis

Then there was Eucalyptus glaucescens, another forestry/amenity introduction of the 70’s, also known and now generally avoided for its aggressive roots, yet here looking beautiful with its grey, lanceolate foliage.  This was the tallest tree on site.

Eucalyptus glaucescens, showing adult foliage

Eucalyptus glaucescens, showing adult foliage

Of course, there was the ubiquitous Conocarpus lancifolius, widely planted still yet also recognised and a danger to any nearby drains, and on it’s way out in popular use.  Except it does make such a good tall hedge, and it has a much nearer native origin, coming from Somalia, Djibouti and Yemen.  I’m not sure that the UAE landscape industry is ready to ditch it just yet.

Conocarpus lancifolius

Conocarpus lancifolius

There was even a palm, Washingtonia robusta, self-seeded around the place.  Much of it was to be found growing underneath the canopy of the P. juliflora, so that at least is not put off by any allelopathic biochemicals from the Prosopis.

Washingtonia robusta

Washingtonia robusta

There were also a few unidentified things, this shrub, for example.  A legume of some kind, if anyone can ID it, please let me know.

Unknown Legume

Unknown Legume

Rose-winged Parakeet

Rose-winged Parakeet

Inhabiting, or at least visiting the site, was a Rose-winged Parakeet.  Another exotic invasive with beautiful form but aggressive tendencies; it seemed appropriate to the moment, somehow.

 

What does this mean for future landscapes and ecology?

 

From a conventional ecology point of view, these plants are all threats, and the threats probably outweigh their usefulness.  So why am I even talking about this?  Clearly, the move towards more naturalistic landscapes draws heavily on native species and would shun all of these species.

Except we have climate change.

Climate change is the elephant in the room, when it comes to ecology, in fact when it comes to sustainability generally and a livable planet overall.  That we have already moved beyond vital tipping points is highly likely; that climate zones are moving away from the equator at a rate too fast for nature to adapt is a fact.  Flora and even some fauna just can’t move regions that quickly.  They will adapt, eventually; but those that are rare, specialist and struggle with change, will die.  The tougher generalists will adapt and survive.  Nature will build a new ecology to reflect the new reality, and it doesn’t mind if it takes a few thousand years to do so.  Only we humans mind and so, if we are to survive, we must adapt our environments to fit the new reality.  It is a sad fact that many cherished plants will eventually die out or move zones.  In the UK, I dread losing our native oaks (I view these as our ghaf tree equivalent), yet we may get Mediterranean species to replace them, such as holm and cork oak.

If you are already positioned in the arid equatorial zones then you have precious few plants that will form your new ecologies and landscapes.  Perhaps the plants I have described above will be UAE naturalized-natives in 100 years’ time and the ghaf and sidr may be gone, or diminished, or moved north.  I hope not, but before we spend vast fortunes on eradication and control of non-natives, we should look to the future.  These aggressive invaders may just form the landscape of our children; I know I’d rather live with a landscape, than none at all.  If there is no landscape, there is no life.  They may, in fact, be here to save us.

Once we grasp this fact, we can look at building new landscapes to suit our changing environments. I’ve written about this before and you can read the articles listed below.  We must be vastly more holistic in our thinking in order to do this and broaden our horizons to understand the new future.  Technology will help us to monitor, collect data and produce working strategies.  Robotics and drones will help manage and control plant communities.  Alongside that, we need a vastly better understanding of soils, microflora and fauna, for the bit of nature that we see is just, literally, the tip of the iceberg.  The selection of tree and shrub species for adaptation is easy, we get this wrong when we don’t deal in whole context thinking eg. only thinking of forestry or ornamental benefits.

The challenge ahead is huge but in a weird way, exciting; it will challenge the human race to grow.  There’s a whole new science to develop and we’d best get on with it.

 

Other articles by ML that relate to this topic:

 

http://www.marklaurence.com/wp/trans-migrational-landscapes-a-survival-strategy-for-the-world/

http://www.marklaurence.com/wp/why-we-can-and-must-create-new-adaptive-ecologies/

http://www.marklaurence.com/wp/trees-climate-change-our-landscapes/

 

 

Posted in Arboriculture, Climate Change, Dubai, UAE, Ecosystem Services, Environment, landscapes, Middle-East, Natural Landscapes, Regenerative Planting, Sustainability, Trees Tagged with: , , , , , , , , , , , , , ,

July 10th, 2016 by Mark Laurence

This review first appeared in Thinking Gardens in February 2016.


This book represents a new wave of thinking about “natural” planting that has been emerging in recent years; actually it has been developing for the last thirty or more years but like all new things, they tend to follow an exponential growth curve. I’d say that right now we’re near the base of the steep upward bit with this one. Left unchecked, exponential growth tends to end in collapse but this idea deserves to stay the course. To do that it has to translate from a style into a design language and that’s what this book is really about.

This is a very US-centric book, unsurprising since Thomas Rainer is from Alabama and Claudia West, though of East German origin, lives in the US. I would have liked her influence to have given the book a more European feel; it would have been richer for it and more globally relevant.

The book has already been reviewed on TG by James Golden but although I’ve read this I’m not referring to it, save for one point. Needless to say, that review is also very US-centric; my purpose is to give a more UK/European viewpoint.

The thinking in this book is very design-led, in which the authors refer to landscape archetypes, which I think is very useful. However, they only select three – grasslands, wood and shrubland and forest. Given the vastness and variety of American climate types (which has just about everything), I’m surprised they didn’t mention desert landscapes, arid-mountainous or Mediterranean (as in Californian coastal regions); I suspect they have simply not worked with these climates, yet to omit them from a listing of archetypes is limiting. It is clear too, that their interest lies mostly in the grassland or prairie archetype.

Desert Archetype

There are many archetypes other than the three mentioned in this book. Desert near Dubai, UAE.

Referring back to the JG review, he wanted to add another archetype, Edges. I would argue that the wood and shrubland archetype is an edge, or rather a transition. Only in farmer’s fields do we have an edge as such. I would think of these archetypes as parts of a sine wave, one transitioning into another as climate and topography dictate. This sine wave also rolls around the globe over time, one archetype superseding another in any given place. Remember that the Sahara desert was woodland just 10,000 years ago, when we emerged from the last ice-age. This fits with the theory that there is no such thing as an ecological climax.

Another interesting thing to come out of this book is the idea of “designed plant communities”. You could say that any grouping of plants together is a designed community but the context they use of grouping plants by habitat-type rather than just their visual look is refreshing. This makes good sense, provided that such a designed grouping is appropriate within its wider environmental context. Taken to its logical extreme, however, you end up with native plants only.

What may be harder to work out is how much of this philosophy fits into a garden. Even the largest garden can’t fit in a whole wood, let alone a prairie, so of course, we must work by inference. This aspect of things is not really discussed in the book and most of the pictures are of large gardens in amazing settings; domains of the lucky few who we landscape designers occasionally get to work for. Yet for the majority of small garden owners, instruction for the adaptation of these principles is missing.

Millenium Park, chicago

The Lurie Garden, Millennium Park, Chicago by Piet Oudolf exemplifies modern Naturalistic planting. This is large ribbons or drifts of plants rather than the species intermingling favoured in this book

Millennium Park, Chichgo

The same garden in November; form is held in the stems and shapes of the seedheads but use of some woody plants might add more winter form?

I feel that the book only really looks at one archetype, that of New Perennial/Prairie style gardens and there is a big focus on this at the moment. I might compare this book with Oudolf & Kingsburys “Planting, a New Perspective”. That book, whilst not getting down to the archetypal design level, is more European in focus, so possibly a good companion read. Yet it too, mostly deals with perennial-based planting, as you would expect from these gents. The work of Nigel Dunnett and James Hitchmough comes to mind too. The fast-changing essence of many of the plant species used means that these perennial plantings are subject to rapid change, even degradation, over time as some of the most desirable and favourite species are so short-lived (Achillea and Echinacea for example).

I think the Wood and Shrubland archetype is the most likely to resonate with those seeking to create a garden, yet the ones of great importance to me, in a European and specifically coastal Southern England context, is that of the unmentioned Mediterranean or Arid-Mountainous archetypes. Whilst some areas of the Mediterranean clearly fit the Wood & Shrubland archetype (ie broadleaf and evergreen woodlands and Maquis), others such as Garigue, Salt Marshes and Rocky Shorelines, do not. I think this range and essence adds up to its own unique archetype. Arid-Mountainous too is quite distinct (although again with areas that fall into the realm of other archetypes), yet gives us wonderful, tough plants like Perovskia. The Dutch biologist Brian Kabbes has done much to inspire and educate us with his exploration of plants in Kyrgyzstan.

Perovskia arbrotanoides

Perovskia arbrotanoides growing wild in the mountains of Kyrgyzstan. Photo by Brian Kabbes

 

To me, one of the biggest drivers in creating naturalistic planting communities has always been about resilience. To my mind, planting should survive without irrigation, so low water-use plants are attractive. I can’t think of a single garden in the UK that couldn’t survive without irrigation, the desire to use pop-up sprinklers is ridiculous and surely industry-driven. Climate is changing now beyond speeds that Nature can shift plants and ecologies around the globe, so it is something we humans must do if we want a future landscape of any description (oh, and for our own survival). So we have to transmigrate landscapes from one continent to another to keep pace; yes, with all the risks that entails when introducing new species (and it would not be just plants we’d have to relocate). So learning about plant communities and how to build them is a vital skill which this book begins to explore, yet could have gone much further in instructing us on.

Mediterranean Archetype

This coastal garden I designed in Southern UK loosely mimics the Mediterranean archetype, and uses a full range of grasses, perennials, sub-shrubs, herbs, shrubs and trees.

 

In the European context then, archetypes other than grassland/prairie might be more useful and translatable into a garden context. That this book has not covered these is not really surprising but it is a mistake to think that the new language of resilient/natural/sustainable landscapes is dominated by perennials and grasses. This aspect is possibly a trend within the underlying drive for a natural interpretation.

A European version of this book is needed, which could perhaps take it to the next level of design language development. In this respect, inspiration can be drawn from another book, “A Pattern Language” by Christopher Alexander, which although about architecture and space, is also about soul, spirit, context and community, realised through the use of a language of patterns. In a very real way, “Planting in a Post-Wild World” attempts to create an archetype-based design language and is a valuable contribution to that. We just need the language to be global, or to see this book as a regionalised attempt to cross boundaries and develop new thinking.

This is an important book and I recommend it; for all its limitations it shows the way to develop landscapes that are truly new and profound.

Posted in Book Review, Design, Environment, landscapes, Natural Landscapes, Regenerative Planting Tagged with: , , , , , , , ,

hazel pruning methods
January 9th, 2016 by Mark Laurence

In my previous post I talked about a regenerative planting methodology for urban landscapes, in which I suggested you would manage, rather than maintain your planting areas. So how exactly do you you do this? Both involve work and the difference is a subtle but important one, in both attitude and application. Think urban forester rather than garden pruner. The picture above illustrates this perfectly, so let me explain.

It shows two hazels in my garden, both planted as young bare-root trees in the winter of 07/08. The one on the left was coppiced down to the ground in the winter of 12/13, the other has been pruned to keep a structure of older wood, with all suckering growth removed annually. What is the difference? The coppiced hazel has been less work overall and has not been touched since it was coppiced, the pruned tree has been pruned annually, which was not great amount of work but this is just one tree. If there were a hundred, it would be a different matter. The main difference is that the pruned tree has catkins, the coppiced tree does not, but I think this is a difference of genetics, rather than pruning technique, as they have always been like that. The shape of the pruned tree is also wider in its spread and will become gnarled as it gets older.

So in terms of management, if you go the coppice route you do nothing much to the trees except coppice them every 4-5 years. I would suggest that 50% of the trees are coppiced so that not all structure is removed at once. Notice that the growth of the coppiced hazel is straighter, making for a productive yield of canes and poles that can be used in the local community. Other trees that can be coppiced include sweet chestnut, lime, alder, ash, willow and hornbeam. Birch and oak will coppice, but from young trees only. Willows and dogwoods grown as bushes for their winter colour can be coppiced or “copparded” (inbetween coppice and pollard) to around 300-600mm every two years to keep the winter stem colours strong.

Salix elaeagnos

Salix elaeagnos (foreground)

By adopting such techniques in our larger masses of urban street planting and parks, we would deliver a more biodiverse, beautiful and biophilic interaction for all concerned. It would also cost less both to establish and possibly to maintain, than traditional planting. The above willow is beautiful and graceful, yet I have seen it all too often used in municipal car-parks and reduced to a-n-other shrub that is caressed all to frequently with the indifference of a hedgetrimmer.

Time to re-wild our inner selves, and our urban landscapes. We can do so much better than the average landscape we see in our towns and cities.

Posted in Arboriculture, Design, Ecosystem Services, Environment, landscapes, My Garden, Regenerative Planting, Trees Tagged with: , , , , , , , , , , , ,

regenerative tree planting methodology
December 29th, 2015 by Mark Laurence

Almost all urban landscapes are contrived and designed, due to their artificial nature and short timescales of development and use.  We see increasing use of mature rootballed trees and extensive hard landscape and this is normal for intense inner urban areas; I do get concerned that the increasing complexity of urban planting systems divorce trees particularly from their natural functions and prevent the occurrence of the biological interactions/communities that go to make up an ecosystem.  For example, I have seen trees planted whose surface levels are around a metre below the surrounding paving level.  No matter how well designed, this seems fundamentally wrong to me.

So I’m thinking that there must be a way of dealing with the majority of less intense landscape zones (especially where there isn’t the financial budget that a high-end development attracts) to provide urban regeneration, ecological restoration and biophilic connection, all on a modest budget.  This would create a new method to allow for wide-spread adoption in urban and suburban zones.  I think the solution comes from Nature’s own process of natural regeneration and a developed philosophy of minimal (but specific) preparation.

silver birch regeneration

silver birch are pioneering species for natural regeneration

Starting from the observation that Nature is very efficient at regenerating itself, what can we do?  Too often, I have seen unnecessary interference in this process.  I still recall that a few years after the great storm of 1987, I walked through some nearby National Trust woodland of pines and birch.  A great deal of damage had been done with many trees blown over.  Birch had however, regrown abundantly from dormant seed and was already three or four foot tall.  The NT then sent in the bulldozers to clear out the fallen wood so the area could be – replanted.  I watched them tracking over all the natural regeneration.  Why didn’t they just leave well alone?  The restoration of the woodland was only slowed down by such clumsy interference and this was not even a productive forest.

If we simply broke up paving in our urban centres and loosened up the sub-base, what would happen?  Nature would soon find a footing and things would start to grow; however, that process would be too slow and unpredictable for human sensibilities.  So what if we did a little more, adding a small amount of topsoil to the rubble, planting small (1+1 year transplants) bare root trees and shrubs,  with plugs of understory forbs, ferns and grasses. Starting so young, we’d generate a successful community in no time.  These could be designed as narrow ribbons – two to four metres wide, inserted into suitable wider areas of paving.

An urban area suitable for natural regeneration

An urban area suitable for natural regeneration

The above area was one I thought would be suitable for such an approach; there are many such areas throughout all urban spaces.  They cry out for regeneration, yet seldom can this be done for lack of adequate finance.  Below is a quick sketch showing how it might look.

Sketch showing regenerative planting

Sketch showing regenerative planting

The benefits of such an approach would be huge.  It would cost far less than using a traditional approach to landscaping such an area, maybe half (I haven’t costed it!).  The care would move from maintenance to management, using a rotational coppice methodology, rather than trim and tidy (which always ruins a plants natural habit. Biodiversity would be hugely enhanced, air pollution mitigation would increase, wind buffering, urban heat island reduction, stormwater runoff (they would act as rain gardens) and of course, our biophilic needs, our connection to nature.

Someone needs to be bold and try it; talk to me…

Posted in Arboriculture, Biophilia, Climate Change, Design, Ecosystem Services, Environment, landscapes, Regenerative Planting, Trees Tagged with: , , , , , , , , , , , , , , , , , ,