Tim Sansom discusses the issue of balancing gardener’s rights to plant our favourite plants with our broader responsibilities to the environment.
This article is found on the The Digger’s Club magazine
We posed the question of whether the Lupins pictured growing in the high country on our last issue’s cover represented a … “perfect integration of exotics and native trees”… as an invitation to get your thoughts about weeds in the Australian landscape.
The issue of exotic (and non-local native) plants is always just at the back door for gardeners in this country. In order to understand the issue we need to recognise that the problem of weeds in Australia is as much about the way we think about nature as it is about our impacts. When we recognise that we are part of the landscape, the divide between what is native and what is exotic, becomes less distinct.
Digger’s Club members are the serious gardeners of Australia, so your views are important in this debate. As you can see in the published letters below, there is a strong feeling that the central issue is one of place. There is a common recognition that the Lupins are aesthetically pleasing, but that they are out of place growing in the fragile alpine environment. In this context they would come under the broadest definition of a weed, ie, “a plant growing out of place”. If the photo had not been taken in the Alps, but in a garden setting, the reaction would have been different because in a garden setting Lupins are well behaved, having no real vector for spread into adjacent areas under Australian conditions.
A New Culture in an Old Land
Lets take a quick look at the history of human impacts on natural ecologies in a country where the impacts of human activity have been obvious for over a thousand years, and compare attitudes and implications with those in Australia. I recently led a garden tour group to the UK and was fascinated by the completely different attitude that English gardeners have towards their gardens and nature.
There is little concern about garden escapees and weediness in the UK because the ecology of Europe has been radically and irreversibly altered by human activity over the last 10,000 years. Exotics dominate the landscape and are not alien but at home. There is no real distinction between areas where humans have an impact and areas where human activity is out of place, a distinction that dominates natural resource management here in Australia.
In Australia it seems to me that agencies involved with environmental weeds see the control of weeds as the end point with little recognition of the land as a whole being a vastly altered ecology. The reality is that our impacts are going to continue, and until we put ourselves into the ecology and appreciate the whole picture as it now stands, we will struggle to find sustainable solutions for the future. This maturing of our attitude to our landscape may well see us being less concerned with plants with minor invasive potential and may even involve the acceptance of some so called weeds in the landscape as components of the new ecologies we are creating. Will we ever be rid of dandelions?
Are Gardeners unfairly blamed?
Recently a report produced by the CSIRO and WWF entitled “Jumping the Garden Fence – Invasive garden plants in Australia and their environmental and agricultural impacts” stated that 66% of naturalised exotic plants in Australia are of garden origin. I’m not going to dispute this figure, but I would like to dispute this as a measure of impact on the environment. If we look at the activities that have most heavily impacted on the biodiversity of the Australian continent, garden escapes are insignificant when compared to land clearing for agriculture and forestry activities. Since white settlement 32% of native vegetation in the intensively used parts of Australia (mainly the agricultural and urban zones) has been cleared or highly modified and in the most densely populated State of Victoria the figure is as high as 63% (according to the 2001 National Land and Water Resources Audit). Weeds are often a consequence of this disturbance, but without the disturbance there would be little opportunity for them to establish. They are a symptom not a cause.
Foresters are still permitted to plant Pinus radiata without governmental restriction, and farmers are being encouraged by some sectors to use Genetically Modified crops such as Canola and Cotton. Our inland rivers are suffering from restricted flows and altered flooding regimes in order that we can grow rice and cotton in the dessert. I’m not wishing to demonise foresters and farmers because most of us rely on farmers for our food and foresters for our building materials. I’m just illustrating the point that the ecological impacts of garde n plants have to be seen on the wider context of habitat change that has occurred in Australia over the last 200 years.
Given that the issue at hand relates to future impacts on the fragmented ecologies remaining in Australia, it is important that the nursery industry takes a pro-active approach. The industry is working closely with government agencies through bodies such as the Nursery and Garden Industry State bodies (a process that Digger’s is involved in). In order to maintain our accreditation growers such as Digger’s have to check the current weed status of all that we sell. There is no such safeguard when you buy from local weekend markets, something worth remembering when you are next wandering the stalls.
What Plants Should Gardeners Use?
Recently Standards Australia has listed a “National Post-Border Weed Risk Management Protocol” (see www.standards.org.au). A more objective system should help to clarify the situation with some disputed species as there are uncertainties at the moment. The plants listed on this page may have some capacity to survive outside cultivation, but does that constitute a threat to biodiversity?
Plants such as Cream Guavas and Olives, have some invasive potential in specific situations but pose little threat elsewhere. It is examples such as these that, we feel, do not warrant a blanket ban, but rather a warning for specific climate zones where they could escape cultivation. Others such as Foxgloves, Irish Strawberry Tree and Lupins, in our experience, pose little threat to undisturbed vegetation and thus we would argue strongly against any limit on their availability. With a standard assessment process now in place, these differences of opinion should be laid to rest.
The Environmental Garden
A simple (and often publicised) remedy to the problems of garden escapes is to plant local native species in your garden, thus providing habitat and eliminating any invasion potential because if they do escape they can only enhance local biodiversity. This concept has some merit, but it also has some significant problems, especially in urbanised areas where disturbance has already happened to such a level that there is no going back. Raised nutrient levels from storm-water run-off and drastically altered microclimates mean that the species adapted to the area prior to clearing, cannot grow there anymore without significant management.
If we want to create gardens that are more environmentally responsible in urban areas we should be looking at growing as much food as we can in these spaces, planting deciduous trees that can provide shade in summer and sun in winter for our living spaces (thus reducing energy consumption) and ensuring that our planting choices will not negatively impact on the environment beyond our gardens.
Read the full article here
