Australian Open Garden Scheme 2011

Wirrapunga was open to the public on the 10th and 11th September 2011 from 10am to 4:30pm as part of the Australian Open Garden Scheme. Photos can be seen on opendayphotos. I spoke at 12noon and 3pm each day. The text of my talk follows:


Wirra = Bush; Apunga is the Goddess of Small Plants.


In June, 1969, I purchased the block of land, on the corner of Stock and Williams Roads Mylor, which is now known as Warrawong Sanctuary. Stock Road is a road about 3 kilometres long, running from Heathfield to Mylor Township. In 1969, there were 45 species of native orchid growing along the sides of Stock Road. Today there are just five. In fact I photographed all these orchids at that time, since I was fascinated by them. I still have the slides and intend to convert them to digital and put them on my website when I have time.

Stock Road is not unique. This gradual loss of species has been happening across Australia ever since Europeans settled it. Probably the same sort of thing happened when aborigines settled it many thousands of years ago.

The question is, why is this happening? To me, the answer is very clear. Consider our vegetable garden, here at Wirrapunga. It supplies us with a year round supply of all the vegetables that we need. It does this because we manage it in such a way so as to get this result.

Similarly, the plants that grew in the Aldgate Valley, 200 years ago, grew there because there was a management, created by the inhabitants of that time, which resulted in that particular eco-system. The bush was full of animals, of all sorts, grazing it. The people who lived here, 200 years ago, may have regularly burnt it.

The missing plants are no longer growing there because now there is a different management in place. Basically it is a “do nothing” management. Can you imagine what would happen to our vegetable garden if we changed to a “do nothing” management? It wouldn’t take long for the vegetation in it to change considerably.

So when I was retired from ESL I returned to my other love – management and understanding of our local bush. Wirrapunga is my attempt to demonstrate how to maintain our local bush for its maximum diversity.


Wirrapunga consists of a total 1.4 hectares (3.5 acres). We use 0.2 hectares (0.5 acre) for living which includes the house, an animal yard and a vegetable garden. The other 1.2 hectares (3 acres), I decided to return to what it was 200 years ago.

I knew that 40 years ago Wirrapunga was a pretty good block of native bushland. It was basically a “cow paddock” but it was never overgrazed or improved. So it had some reasonable native vegetation on it.

However when we purchased the property it was a different story. It had been left to its own resources. It was covered in blackberries, broom and gorse. A house had been built on it and an English garden had been commenced. An irrigation system had been installed. Lawns has been sown and deciduous trees planted. In short there was little native vegetation left.

However, I have great faith in evolution. Plants don’t just disappear like that. I was confident that their seeds would be still in the soil waiting for the right set of conditions to blossom.


I had thought about this project as I had watched the orchids disappear from Stock Road. There would be five phases to my plan, although they overlap considerably.

Stage 1: Remove all non-indigenous vegetation (this stage is generally called “Bush Care”);
Stage 2: Encourage as many indigenous species to return by themselves (this stage is generally called “Flora Restoration”);
Stage 3: Source the remainder of species from wherever I could and physically return them (this stage is generally called “Gardening”);
Stage 4: Management of bio-diversity; and              
Stage 5: Wildlife habitat.

If I attempt to put some numbers to what I am trying to do, it goes something like this: There were about 600 species of plants growing in the Aldgate Valley 200 years ago. Before we commenced Wirrapunga there were about 300 species of indigenous plants, remaining in the Aldgate Valley. The other 300 species still grow within 10 kilometres of the Aldgate Valley.

Of the total 600 species, referred to above, about 100 are now classed as rare, endangered or vulnerable.

Let me describe the results so far.


Ten years ago there were between 20 to 40 species of indigenous plants at Wirrapunga.

Ten years into the plan the removal of non-indigenous vegetation is under control but I will have to continue for a number of years to come. However! Each year I am now able to remove all introduced plants before they seed or reproduce. Last year was the first year I achieved this goal.

Over 200 species returned under Stage 2. These included a number of rare species. This far exceeded my best expectations. I now expect the rate of return of species by themselves to slow continually.

I have been able to source and physically return a further 100 species. Therefore, at present, Wirrapunga boasts over 300 species of plants that are indigenous to the Aldgate Valley and sourced within 10 kilometres of the Aldgate Valley.

Let me now describe the stages a bit more thoroughly. I repeat that the various stages interrelate and overlap with each other:

Stage 1:

This is about removal of non indigenous plants. However it is inextricably tied in with stage 2. I believe it needs careful explanation. When weeds such as blackberries (or any other weed) are well established then it is not difficult to remove them. After they are removed there is a burst of germination of new plants, mostly blackberries or whatever has just been removed. However, amongst the weeds that germinate are a few indigenous seedlings which have been patiently waiting for the right set of events to trigger their germination.

It is important, at this stage, to weed out the unwanted plants very carefully leaving the wanted plants. I believe that seeds can lie dormant, in the soil, for probably a hundred years if events do not trigger their germination. If their germination is triggered and then they are not able to flourish and reproduce, thus again building their seed-bank in the soil, this species could well be lost. A good example of seeds longevity was given by the recent rains in the arid lands where species unseen for generations have miraculously reappeared.

On the other hand, if the regrowth of weeds is not managed then the wanted species, that have returned, will be lost because of competition of the weeds. They have beaten these plants once. That is why they disappeared. They will do it again if allowed.

The point here is that management of regrowth is a much bigger job than the original removal of weeds and this is where I notice the most damage being done. It is so easy to clear out a well established weed patch. I give an example.

Suppose you have an established broom forest. There would be, say, a bush every 4 metres. Therefore there would be about 600 broom plants per hectare. These are fairly easy to remove by hand. After they have been removed, broom seedlings will germinate about 2 cm apart. That is 25 million per hectare. This is now impossible to remove by hand so they would be allowed to regrow or they will be sprayed or removed somehow in bulk. In either case any seedlings of rare plants that have been waiting patiently to germinate are destroyed.

It is imperative, therefore, that weed removal not be overdone. I have found that the careful removal of the first regrowth germination of weeds takes about ten times the effort of the original removal. It took me five years to get from the top end of Wirrapunga to the bottom in the first removal. I should have spread it over ten years.

About 40% of the viable seeds in the soil germinate after an event triggering germination. This means that the 25 million seedlings removed after the first germination will be reduced to 10 million on the second germination. And so on until the area is stabilised with wanted plants. After that the occasional removal will continue forever.

Stage 2:

Part of stage 2 has been discussed under stage 1. However, there is another problem other than with just introduced species. For example there are indigenous woody weeds as well as non-indigenous woody weeds. In every eco-system there are more vigorous species that can overtake the less vigorous species if events allow it.

Plants have evolved over millions of years to respond to certain conditions and events.

The management regime which allowed the bio-diversity of the Aldgate Valley to be what it was 200 years ago, no longer applies. If a block of bushland is left to its own resources except for the removal of exotics plants then it will stabilise with about 40 species. This is much less than the 600 that occurred in the Aldgate Valley 200 years ago.

Basically this means that areas must always be available for new, less vigorous, small species to inhabit. Careful attention must be given to managing more aggressive species from overcoming less aggressive species.

In short, to get the best out of a bush garden, it has to be gardened. Two hundred years ago the Adelaide Hills was grassy woodland. On the 5th June 1851, just 15 years after the first Europeans arrived in South Australia, Hugh Proby wrote a letter home to England soon after arriving in Adelaide. He spoke of the vegetation of Mount Lofty – how he could ride a horse going along “most excellent cantering ground for any distance”. Try cantering a horse through Cleland National Park today.

However! It is interesting to look at the makeup of this grassland. Over 80% were not grasses but other small plants. Orchids and lilies abound. The Adelaide Hills had an incredible biodiversity of plants and animals. Alas – today they are all but gone.

Stage 3:

This should be one of the easy stages but it is not easy at all. The problem is that we have a Department of Environment who sees their job as ensuring the extinction of as many species as possible. I expect you to be shocked by this statement so let me explain.

There are some species of living things in the world that are in trouble because of exploitation. However, compared with the overall number there are not many. Let me take the plants that are indigenous to the Aldgate Valley. Of the approximate 600 species, 150 are classed as rare. They are not rare because of exploitation. In fact if most of them appeared on someone’s block they would pull them out as a weed.

Let me name a few. Sweet Hound Tongue, Crumbweed, Common Bow-flower, Swamp Crassula, Bitter Cress, Short Twig-rush, Leafy Bog-rush. Woodland Spurge, Lobed Wallaby Grass, Bent-grass, etc. Do these sound like plants open to exploitation?

Let us consider one that could be – The White Spider Orchid. It was called the common spider orchid when I came to the Aldgate Valley over 40 years ago. Why is it endangered today? Well! Let me tell you. It is far from being exploited. This spider orchid is pollinated by attracting insects by pretending it has some nectar. Of course it is all trickery but anyway, an insect calls in hoping to get a feed and picks up its pollen (each flower has just one pollen ball which is picked up by the first insect to visit). The insect has just been tricked. It is not going to set out looking for more white spider orchids, it calls in at the next flower which may have nectar. So it deposits its precious cargo in a plum tree or something. The point is that for this to be an effective pollination method there has to be enough white spider orchids. They are now below the critical number. They are no longer being pollinated because they have lost their pollinating agent.

Of course the solution is to go and pollinate some. They are very easy to pollinate. You just use a stick of dead grass to pick up a ball of pollen from one orchid and deposit it on a few others. I can pollinate several hundred in an hour at Wirrapunga but guess what? I am not allowed to interfere with endangered species. So! The white spider orchid disappears and no-one even notices.

Every year our local council sprays the vegetation along the edge of Aldgate Valley Road. Every year they kill rare and endangered species of plants. Yet I am not even allowed to collect the seeds from them before they destroy them.

Stage 4:

Stage 4 is just about management of biodiversity by ensuring that the more vigorous plants do not overcome less vigorous species. This is about trying to imitate the events which occurred in the Aldgate Valley 200 years ago. Then, this would have been carried out by fire and animals grazing. Now, I have to simulate this. Most of this I simply do with a heavy duty lawn mower. I try to mow each area every few years.

As Wirrapunga improves, year by year, more have become interested in the project. Last year it was awarded with a Certificate of Excellence under the Sustainable Landscapes Native Garden Awards. This year it has been invited into the Australian Open Garden Scheme. As such I believe it will be the first indigenous garden in the Open Garden Scheme. But hopefully, it will not be the last.

I t is my strong belief that indigenous native gardens should become the norm in gardening. I plan to do my best to bring this about.

Stage 5:

Stage 5 is about making the garden a complete natural community with allowance made for all the animals, from worms to bandicoots, being able to live there as they once did.

This means piles of debris and rocks, pools of water, nest boxes, fox and cat free areas, native bee and wasp homes, overwintering quarters for ladybirds, etc etc etc.

If you can think of anything I could have, but don’t have, please tell me and I will do my best.