Edges, boundaries and paths

Cultivating the Patch is throwing up interesting questions about edges, boundaries and paths. It's a rectangle of land with minimal boundaries: a large-mesh wire fence on the north and east separating it from the neighbours' properties; a 2 metre wooden fence on the south separating it from the school oval and no boundary on the west other than Jill's and Mike's vineyard.

On the minus side, that means that there's little to block the passage of wind, rabbits and the occasional errant dog. On the plus side, there are none of the issues with shade that we have to deal with in our home garden, caused by mature trees in our and our neighbours' yards, and of course our 2-storey house. The Patch was really a horticultural blank slate.

The Patch - June 2011

Faced with a nice big block of land to grow stuff on, my tendency (and I suspect I'm not alone in this) is to think of growing space, not access, and to begrudge any land dedicated to paths and barriers.

But paths and barriers are necessary. Foot and wheelbarrow traffic compacts soil, so you don't want to walk on land you're going to grow plants in. Aggressive running grasses and other tough running weeds (we're 'blessed' with kikuyu and blanket/carpet weed) would quickly overrun the cultivated land without well-defined borders that can be 'patrolled' for incursions.

I've tried to build some Permaculture principles into how I tackle the issue of barriers – the Patch is defined to the east and west by borders of deep-rooted, perennial plants – primarily comfrey and lucerne, which resist the encroachment of running weeds, provide useful nutrients and mulch to the garden and require little maintenance or irrigation.

To the north, a wattle border will eventually be about 2 metres high and diversified with sheokes, blueberries, etc. to provide shelter from hot northerlies, mulch and enrichment for the garden and some fruit for us.

I'm happy with how those solutions are evolving, but within the garden I feel the need for permanent paths, borders and subdivisions, and I'm not entirely happy with what I've done so far in that regard. One of the issues is the tension between the Permaculture approach I've recently learned – which values edge, diversity and curvilinear forms – and the traditional European organic gardener's approach, which wants straight lines and rectangular beds. There are advantages to both approaches and I haven't yet found a balance which works for us.

The two weeks I spent at Milkwood Permaculture in NSW brought home to me that there is scope for both approaches within an enterprise which is inspired by Permaculture principles. On the one hand they have a nascent forest garden which in years to come will probably be intensely productive with little ongoing maintenance; on the other hand most of their food in these early years is produced in a very traditional looking, labour-intensive organic market garden.

Perma-thoughts, 2

Here's an example of how my Permaculture course has changed my perspective on elements of the Patch:

On the northern boundary we're establishing a windbreak against hot, drying winds. At the moment, this consists of 15 Flinders Ranges wattle saplings. All but one are doing well, and should start to be effective in the next 24-36 months. I was quite pleased with this idea when I first thought of it: 'Good idea to create a microclimate, Steve!' I thought.

Will eventually be a windbreak: 15 tiny wattle seedlings , Aug 2011

Now, applying some Permaculture principles, I can see ways to make it a whole lot better:

Principle: Build diverse, stable ecosystems.

OK, a 15 x 2 metre windbreak (eventual mature size) isn't exactly an ecosystem. But what if I planted sheokes on the leeward side of the wattles, and grew a small-leafed (because not rampant) hardenbergia up the sheokes when established, and dug a swale to catch water runoff, and sowed the bank of the swale with dichondra and native violets, and planted blueberries in the lee of the windbreak? And put logs in the swale to provide habitat for lizards and amphibians?

Would this be an ecosystem, or just a collection of plants and landscape features? Let's have a look:

The wattles and the sheokes together will make a more effective windbreak; both are nitrogen fixing. When they are cut back (mulch for the veg beds), some of their root mass will also die off, making nitrogen available to the soil. Hardenbergia is also nitrogen fixing, so we have three plant species improving the soil. Blueberries on the leeward fringe of the windbreak will benefit from the added nitrogen, and also the acidic environment provided by the mulch of sheoke needles.

All of these are flowering plants and will provide forage for bees and nectar-eating birds. In addition the swale should become an ephemeral wetland, attracting the numerous frogs from the surrounding area - we're lucky to have two established wetlands to the northeast and northwest of the site.

So this begins to look like a functioning ecosystem, with beneficial interactions between the various species. In time further species would be introduced (or colonise by themselves) and it would become more diverse.

Principle: Every element of a design should function in many ways.

This is also referred to as 'stacking' functions. How does our windbreak fit in with this?

As envisaged above, it now serves the following functions:

• reduces the impact of hot, drying winds
• provides mulch for veg beds
• provides forage for bees (pollinators, suppliers of honey)
• provides habitat for insectivorous birds, reptiles and amphibians (pest control)
• provides fruit
• improves soil nitrogen
• improves water infiltration
• removes the need for mowing (saves labour)

Now, not all aspects of the plan will turn out as envisaged. For example, it may be that blueberries just won't flourish where I want them, so I would have to use other berries. That would tie in with other Permaculture principles:

Apply self-regulation and accept feedback.
Use small and slow solutions. (Otherwise referred to as incremental design.)
Creatively use and respond to change.