WE NEED TO TALK ABOUT CONCRETE
Did you know that the environmental impacts of concrete are out of control and that the carbon dioxide produced from the production of concrete are a close second to fossil fuel emission? Did you also know that concrete is the second most consumed substance on earth after water?
Composed of primarily cement (a powdery substance derived from the process called calcination where calcium carbonate decomposes to form calcium oxide and carbon dioxide) and clay, when mixed with water, sand and gravel, it creates concrete.
The first law of thermodynamics states that energy production needs to be curbed if we believe the law of conversion of energy. With this latter law, energy can be transformed from one form to another, but is unable to be created or destroyed. In other words, the energy of this isolated system remains constant. Therefore without access to an external energy source, there is not an unlimited amount of energy available.
We are currently using the available energy at a rapid pace. It cannot continue. Fossil fuels are definitely a problem, but so is concrete production. Cement manufacturing is highly energy – and – emissions intensive because of the extreme heat required to produce it. It also releases a significant amount of CO2.
Concrete is used throughout the building industry for homes and commercial premises. It is the most widely used building material because of its strength in many situations. So if this use continues, then the external element, within gardens, needs to be considered. Is this outside use appropriate?
As a sustainable landscape designer, designing and implementing sustainable gardens for over 20 years, I believe that it is time that we considered the massive environmental impacts that many landscape designers are causing.
If retaining walls are required, in my area, Cypress Pine is a wonderful product sold as sleepers. Its longevity is around 100 years I have been told and it is naturally bug resistant so has none of the toxins as does treated pine. These sleepers can then be used as the retaining wall. Old fashioned? Is there a problem with this, if it is in sync with nature? There is, in my opinion, no place for concrete. I don’t need to use concrete in my designs, because I work with nature and use what is naturally occurring.
Another form of retaining is where a site has naturally occurring large rocks or boulders that require only small machinery to move them in to place. Anything that requires cranes or large machines should be totally avoided, because these machines are destroying the natural ecology of a site. This is unsustainable practice. These workable rocks can be placed in judicious spaces along a slope to help bind the soil, in conjunction with appropriate plants that act as soil binders. Small rocks can be used here to help hold the soil while the plants are young. And when the path is taken across the slope, the steepness is considerably reduced. The rocks then become a feature within the curves of the path.
The continuous use of concrete is strongly atypical of a normal, sustainable garden – it is not clever garden design; it increases the project cost considerably – it is unnecssary especially considering the environmental impacts. And this style of landscape design is becoming the norm.
The right way to design a garden, and this is my opinion, but it wins awards, is to suit the plant to the site and soil. Not modify the soil to suit the plant that you want to grow. It’s the same as a person wanting to grow Camellias where they have alkaline soil. The naïve will try to change the pH of the soil by adding sulphur or peat – this is a very slow process. Why not put the Camellia in a pot where the soil can be regulated properly? And then put a plant in the ground that is suited to that position – and it should thrive!
According to the Concise Oxford Dictionery, a ‘garden’ is ‘a piece of ground devoted to growing flowers, fruit or vegetables’. There is no mention of rendered, raised planter boxes or concrete en masse. A garden is about plants.
As a Designer there are so many more sustainable alternatives to concrete – its just a matter of changing direction and taking the client with you. If you have a passion, and confidence in what you are talking about, the client will respect the advice when sustainable alternatives are suggested and why.
We all really need to start becoming more aware of the excessive use of concrete. And it is excessive. We need to start the conversation with others about this worldwide problem – it has to stop. We are all now fully aware of the impacts of fossil fuels, with the exception of those who lack any capacity for common-sense, so we need to make the world more aware of the effects of concrete. It is a major global problem that, in my opinion, needs addressing now.
An oft misused word
One hears the word ’sustainable’ bandied around a lot in many businesses. But how many people really understand what the word means, and the implications of doing the exact opposite? I want to be a leader in bringing about change in how we address landscape design for both domestic and commercial sites.
Sustainable development, now referred to as ‘sustainability’, according to the World Commission on Environment and Development, 1987, is “Development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. In other words, future generations should be no worse off than the current generation with current practice. Also for consideration is the robustness and stability of ecosystems, so that they can continue to flourish unimpeded.
A sustainable garden, from the outset, works with the site as it presents. It is a completely different concept to the typical manufactured garden with rendered retaining walls, masses of immaculate paving, lavish lighting and so on. There are minimal earthworks; retaining walls are only used if absolutely necessary – in fact I like to work with slopes using plants to bind the site; I use aggregate as an alternative to pristine paving and I don’t use lighting as this frightens the birds. But good design is paramount with a professional sustainable garden – these gardens need real flair, to make them stand apart from Joe Blog’s down the road.
I was the former owner/designer of Australia’s first and only Ecotourism garden; it was a wonderful learning experience going through the rigorous certification procedure. And I have been able to adapt so much of that experience into my current model for sustainable landscapes.
I have attended many of the Landscape Designer’s Conferences held biennially in Melbourne. Most of the speakers are from overseas, with an overriding consensus of opinion amongst these speakers being the movement back towards sustainable gardens.
I am a regional landscape designer. Often our sites are large, and so as a genuine sustainable advocate, I break up these sites with plants. Plants are essential for carbon sequestration, provide biodiversity to a garden and when correctly used, aid the ecology of the site, especially in areas with drainage issues.
A good sustainable landscape designer needs to have a massive repertoire of plant knowledge in order to be able to effectively handle any difficult site with plants that will work in that situation. I use plants to soak up poorly drained areas and plants can be used to bind sand on coastal dunes.
Some earthworks are often required initially, but it needs to be minimised. I have seen too many photos of large excavators being used on sites to place massive rocks into situation, in the name of sustainability. Significant engineering and construction is taking place in these gardens – the whole ecology of the site is being eroded with these actions.
A true sustainable garden uses an extensive range of native plants [but they can also be exotic as long as there is variety] suited to the soil for increased biodiversity to the site; limits earthworks; minimises all construction and has no hard landscaping. It should also provide insulation to the home as climate change concerns become more evident. It’s that easy. I like to call a sustainable garden, because of its modesty – elegant.
Inheriting an existing garden
When we purchased our garden, now called Timandra by the Sea, in 2008, there was already a garden in situ, on the upper level of the property. The previous owners had formed this garden out of many different plants that mostly grew from seed, under a considerable canopy that at the time of purchase was still growing.
It has been a long and hard battle to control these seeding plants. As well as the Wandering Jew and other ‘lovelies’ which are so difficult to eradicate, more time is spent trying to manage this area than any other part of the now considerably bigger garden. Of course lawns will always be a weekly chore, but I love our lawns, as a contrast within the design of our site.
The canopy has continued to grow with our care. This is a mixture of deciduous trees, gums, tall bottlebrush and weeping myrtles. It was the trees that so attracted me to our 1 acre property.
These trees were over-planted and have had to be thinned. Each plant now performs better, given the room to expand both above ground and below.
Our ‘rainforest’, initially just a band of gums in the middle third of the site, and predominantly Eucalyptus leucoxylon varieties, was a real mess upon purchase with a massed underplanting of Euphorbia wulfenii and other such weedy ‘gems’. There were even dead climbing roses amongst the mix! We have since cleared this area, including raising the canopy of each gum so that you get that massed trunk effect of a rainforest while also increasing the vertical aspect of the garden. This has made the overall sensation of the garden appear bigger and gives the middle, sloping section a real wow effect as you enter it. The entire area has now been underplanted using plants synonymous with a rainforest – and they are thriving.
This middle section is on a slope; around a 60 degree drop at its worst. The previous owners made concrete steps going almost straight down, meaning that the steps are also really steep. It would have been far better to lengthen the drop by taking the path across the slope instead – there is ample room for this. In the desire to retain the sustainable factor within Timandra, and because of the significant cost and labour required to remove them, we have opted to keep them.
Both the top and bottom thirds of the property are flat. So as you exit our rainforest, the bottom area opens to a north facing area that is flat. From the canopied garden just left, it is a remarkably different experience entering this entirely different garden. You catch glimpses of it from the path leading to this bottom garden, but this new area is so different that it often causes comment by viewers.
There is lawn here, as in the top or front garden, but in the top area the lawn is largely hidden from view until you enter it. This bottom lawn area encircles a garden, with lawns surrounding the lawn on each side also. The lateral gardens have meandering paths through them, also found throughout the rest of the garden.
Children in particular love meandering paths. Paths help to break up a wide expanse of garden, creating more interest to viewers. And when you have big trees, as in Timandra, these paths enable tree roots to grow unhindered from competition.
In the quest to provide windbreaks on the north-east, north and north-west boundaries, the previous owners planted trees. But they have planted whoppers. Eucalyptus globulus and Eucalyptus grandis are examples. And of course they are almost under a major power line that, annually, warrants heated discussion with tree choppers directed to decimate all growth anywhere near the lines. As a horticulturist, one who aims to retain trees in peak health, I have managed to get my way about how the trees are pruned. But as soon as our property changes hands, I feel that these beauties will be doomed. Why do people plant such big trees without thought?
The negative factor of these very big trees on the northern boundaries is considerable in the design and plant selection. Throughout winter, the garden south of the trees’ shadows is shrouded in darkness. But many of these plants during summer are exposed to a lot of western sun. The design and plant selection here has caused a real conundrum for me. But surprisingly they all work. I would never consider removing these majestic specimens. They are now well integrated into the garden.
The large trees were in the bottom space upon purchase, but most of the bottom garden was used to house large earthworks machinery of the former owners. So we have rubbish left by such machines, namely diesoline and oil spills. We find nuts, bolts, rusted metal, glass and so on regularly in this area. I’m sure that this affects plant viability in these parts of the garden. This is why knowing the history of a site can be so important to a garden.
With the knowledge of this machinery history, I have added odd sculptures around this lowest area. Many of these idiosyncratic pieces have come from our local recycling yard and from scrounging through similar junk yards as I travel.
We have also used remnants of our former front fence that had the property numbers on them. This to me is a very important design element in all garden that I design – to include part of the site’s history within the design. But it needs to be quirky, not kitsch; there is an enormous difference. If you are unsure of the difference, then steer clear.
Timandra has changed enormously since our purchase. Gone are the gaudy, flowery plants of former owners. It is now a garden of serenity. It is a haven for a large range of resident and migratory birds and our furry friends, the koalas. My former gardens, all in South Australia, were composed of mostly exotic plants. I am now finding that the Australian native plant gives so much more intense satisfaction to me, because of the joy from the wildlife. We provide plenty of water, but no food. There is an ample, natural supply of food for a magnitude of different fauna – we don’t need to artificially feed them.