Alison AplinSustainability in garden design

This is a subject that is very dear to my heart. I get quite passionate about the subject so do apologise if I offend any readers. I have been a sustainable garden advocate now for at least 20 years – well before most people even considered what sustainable gardens really meant. So I have put a lot of mental energy into working out why I think the way that I do about how we design gardens and how we manage them into the future. I was also the only owner/designer of a garden that was accredited with Ecotourism Australia for its sustainability credentials.

Australian Native Garden in Adelaide Botanic Gardens

Australian Native Garden in Adelaide Botanic Gardens

Excellent examples of sustainable gardens are often Botanic Gardens, the Adelaide Botanic Garden in particular being a very good example. I spent much of my childhood wandering through this special place, learning a respect for different plants and their juxtaposition with each other. It was never about hard landscaping – it has always been about plants. And this to me is what maketh a garden.

Many of the designs being portrayed by students from landscape design institutions are to me evidence of ‘learnt design’, not natural instinct. My instinct will always be to use the site as is presented, even with a difficult slope. This then enables natural movement of water over the site, without having to reconstruct a drainage system to manage storm water.

Design Sandra Heggen

Design Sandra Heggen

Am I being old-fashioned? Some, in fact many, may say yes, but my clients when shown pictures of gardens that are award winning ‘sustainable’ gardens, always claim that they want more plants with a far greater variety of plant material used. The real sustainable advocate understands the need for biodiversity in all of its forms, especially plants and trees that encourage different birds, insects, lizards etc. Not just one or 2 plants, but a mass of them providing understorey as well as canopy.

In order to make this garden that some may find boring, because of the lack of the trendy outdoor room, brazier pit, painted panels and so on, I prefer the more subtle use of receptacles for bird baths, quirky sculpture, recycled bits and pieces from the site that can be used to make its own ‘picture’ when grouped together. These ideas are classic and will last indefinitely, whereas the outdoor rooms, with all of the maintance that is entailed will, I predict, disappear as with all fads.

Design Fiona Brockhoff

Design Fiona Brockhoff


I feel that the landscape designer who can create sustainable, though visually interesting gardens in coastal regions are leaders in this field. Fiona Brockoff is a great example of a designer who uses indigenous plants totally suited to the harsh conditions created by salt laden winds, which according to the CSIRO are increasing in salinity. I have seen some of Fiona’s work and find it really inspiring – I love her creativity; it is so natural and in sync with the surrounding space.



Too often I see retaining walls used as a feature on a flat site. These walls are often rendered, totally at odds with sustainability because of the products used, drainage is often impeded, and imported soil needs to be brought in to fill the garden space. Have you ever done a pH test of this soil? In my region, there is not one supplier that sells soil with a pH less than 10! This is toxic to plant material, so why use it?

Stone wall building at the Chelsea Flower Show - this is not sustainable gardening

Stone wall building at a garden show – this is not sustainable gardening

There are occasions when the soil that is purchased, especially ‘organic soil’, will have a pH of between 6.5 to 7.5 depending on the amount of organic matter that has been added, but this matter is added to the most inert soil that can be found. The soil too often comes from creek beds at great distance, taken to a depot where organic matter is added under high heat. The soil is then sold commercially as ‘organic’. I do stress though, that not all soil that is purchased is so badly prepared. But from my many years of landscaping experience, this is too often the case.

Excavation of a show garden landscaping site

Excavation of a show garden landscaping site

The extreme alkalinity can be caused by 2 possible factors – either naturally occuring limestone [calcium carbonate] in the soil or the problem is caused by salt or leaching of sodium from sodic soils, especially if sourced from inland sites. Both will affect the pH. And unfortunately this purchased soil almost always reverts to its original inert form. This is why so often plants growing in imported soil fail – it is the toxicity of the imported soil and possibly inappropriate plant selection that will not cope with the increasing alkalinity as the soil reverts, that is the problem.

There is just not enough quality topsoil to go around. If people want to buy soil, then it has to be manufactured because of the lack of supply. Why not instead, just work with the flat site? From my considerable experience, when the site is not manufactured, the garden not only looks a lot better once mature, but the garden will last long-term.

Natural locally-sourced mulch at Silky Oaks, Oakdale

Natural locally-sourced mulch at Silky Oaks, Oakdale

Another issue is mulch. The mulch that we used to purchase for our client’s gardens was carted great distances. I now use locally sourced council mulch – not only is it far cheaper, but it is a local product, looks great and is far better for the soil than pine bark. And don’t get me started on the hideous red and black rubbish that is sold as mulch. I can only imagine the toxins that are in the dyes used to colour the bark.

River pebbles are also a misnomer in regard to sustainability. I like the look of them like most people for a native garden, but they are too often not sustainably sourced and once again cover great distances before sale. One should question whether the removal of vast numbers of river pebbles from any water course is a sustainable action, and these are used in great quantity by some landscapers. Surely locally sourced gravels are more sustainable and they also look good.

Shade trees

Shade trees reduce the need for air conditioning

Another thought that needs discussion here is the need to be visionary with our garden designs. Good domestic gardens should have insulating qualities that reduce the need for excessive air-conditiong. Trees have a remarkable impact here. We also need to be cognisant of the fact that in Australia in particular, our climate is changing [whether you like it or not!]. It is getting hotter and in the southern parts, drier and our gardens need to reflect these changes. So good garden design needs to be visionary. And landscapers worth their weight will bear this in mind as they design gardens for their clients.

One of the projects that we have coming up is the total replacement of a garden put in place just 3 years ago after our client’s home was completed. The garden is a disaster – totally incorrect plants were used with large surface-rooting gums too close to the home, a seeded lawn was planted in subsoil clay, garden edges were done with incorrect timbers and the design itself was substandard – and the list goes on. So these poor clients now have to pay twice for a garden that should last indefinitely if done properly.

These ideas are only the tip of the iceberg when it comes to sustainable practice with our gardens. I am not suggesting that we emulate the bush in our gardens; even I advocate some sense of design and formality – even with a native garden. I just think that the gardens being paraded today as ‘winning’ gardens are sometimes too contrived and too fad driven. And there is a sameness about many of them, which suggests that the designers have learnt design, instead of using natural design instinct to guide them. There is a wealth of difference between the finished designs.

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Alison Aplin

About Alison Aplin

Alison is a passionate, multi award winning sustainable landscape designer, Horticulturist and arborist. She has been the owner and designer of 2 Ecotourism gardens that have both won significant awards. Her writing is based on knowledge, empirical learning which is essential to sustainable ethic, and a questioning mind leading to much research. Her articles are often controversial - with a disclaimer that she is responsible for the written matter, and not Garden Drum. A deeply caring person about the natural environment, Alison's writing endeavours to explain why sustainable landscapes are so important. Without people like her, they will be lost and gardens will become merely concrete

4 thoughts on “Sustainability in garden design

  1. Hi Alison.
    Thank you for your post I couldn’t agree more. Until recently I have struggled to convince clients of the value of sustainable design as their main concern was to “keep up with the jones” and have what everyone else has. I now only work for enlightened clients and now each of my designs are unique as each client and site is unique. Happy clients happy designer.

    • I also agree with your statements Stephen. I am also selective with my clients as am confident that my way is the way of the future. Some people won’t listen, so I suggest that they find an alternative designer who will do as they ask i.e. a labourer.
      Sustainable gardens to me are not manufactured; they are simple in their presence and mine always follow the KISS principle.
      I’m pleased to hear that there are other designers who think like me.

  2. Hi,
    A great article and one that should be widely read.. I am not a professional designer but have been gardening with native plants for over 40 years and I agree with your main points.
    I live in Sydney’s Hornsby Shire and about two years ago they changed their tree preservation policy to one that only requires permission to remove a tree is of it is indigenous. As a result there has been a huge (no I am not joking) loss of mature trees. Many houses are now tree less and in full sun. The street scape has been altered and in some streets near me have only a few trees over 3meters high.
    You are correct regarding importing soil. I tried that on my flat block about 20 years ago and all was well for a year or two until the organic matter was used up and I was left with an inert mass that water would not soak into.
    As for the sameness of garden one only need to look at new houses in NSWs Southern highlands – so predictable – A weeping cherry, Iceberg roses up the driveway together with a box hedge etc etc. Oh so predictable.
    Designing gardens with native plants is not an easy task as there needs to be a certain degree of formality, especially in small suburban gardens and this only come about by experience and a good eye for design.


    • Thanks for your response Jeff. Sorry for the late reply.
      I have noticed numerous street trees in some of the towns in my local shire appear to have been earmarked for removal. Most are bottlebrush and are not particularly good specimens for main roads – more appropriate trees should have been planted in the first instance. But these trees are better than nothing for the biodiversity effect.

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