The use of “Edge” in garden design is essential to stimulate biodiversity: here is how to do it

In permaculture design, we often talk about using edges. But it can be a confusing concept for those who aren’t necessarily very familiar with permaculture ideas. When we talk about using the border or maximizing the border, what we are really talking about are the ecotones between two distinct types of ecosystems. Here’s some more information to demystify the concept for those who aren’t already familiar with the general ideas involved.

What is an ecotone?

An ecotone is a boundary between two types of ecosystems or biological communities. For example, the boundary between a forest or wooded area and an open grassland, or where terrestrial ecosystems meet aquatic or marine environments.

These boundaries can be hard divisions, where one type of ecosystem suddenly shifts to the next, or fuzzy boundaries where one ecosystem gradually shifts to another.

These marginal or peripheral areas where one type of ecosystem mixes with another can often be the areas most rich in species diversity.

Why Edge is important

We are talking about maximizing the advantage in permaculture design, because one of our main goals is to get the most out of biodiversity, not only in terms of the number of species, but in terms of the number of interactions. beneficial between species. The more beneficial interactions there are between the elements of a system, the more stable and resilient that system will be.

Thus, by maximizing the edge areas, where one type of environment from vegetation type shifts to another, permaculture designers will seek to increase the stability and resilience of the system.

The edges are places where you will find species from two distinct ecosystem types, as well as new species allowed to thrive due to the unique environmental conditions created by the merging of species from the two ecosystem types.

Suppose, for example, that a woodland environment supports species A, B, and C. And grasslands support species D, E, and F. An ecotone in between could support AF, plus G, H, and I (due to increased light levels, greater water availability or other environmental factors).

Perhaps this makes it a little easier to understand why edging is so important when it comes to increasing biodiversity in a garden. If you look at the edges of a woodland or forest, the riparian zone along a river or other natural examples, you will more easily understand this “edge effect”.

Using Edges in Garden Design

Using edging in garden design is simply using this natural phenomenon to increase the biodiversity and productivity of a garden.

Thinking about the shapes of flower beds and borders, walkways, ponds, and other features of garden design can help us maximize the amount of border environment we can create. For example, rather than creating straight paths, we can create winding paths with much longer edges.

We can create food forests or woodland gardens with meandering edges, perhaps bypassing the edge of the system to create solar traps in the south (in the northern hemisphere) where plants that love soft, sheltered conditions can squeeze in. ‘flourish.

We can create hedges and other planting patterns between garden areas, dividing the space and creating a range of new microclimates and growing conditions.

We can make flower beds with irregular or curved shapes, wavy or with a keyhole design, rather than sticking to simple rectangular growing areas or borders with straight lines. Or may include more smaller beds rather than fewer larger beds.

And by staggering the planting to create zigzag rows rather than straight lines, we can maximize the number of plants that can be included in a grow area.


A spiral of herbs.
OK-Photography / Getty Images

Using patterns from nature can help us understand how edges can be maximized. A key example of this is the spiral shape. This is commonly used, for example, to create a “herb spiral” – a concept that allows a range of herbs that like different conditions to be grown in a smaller area. Shaped like a cone, this concept maximizes both the growing area and the border, creating a range of different microclimates.

In the same space, you can create a pond with curved, meandering sides that have a lot more edges than a simple circular pond.

There are many more examples, but the above shows that what is useful to understand in larger scale natural systems can also be useful in the design of a garden.

Using borders and valuing the productive and abundant boundaries between different organic communities can help us make the most of the space available in our gardens and emulate nature and the garden in a more sustainable and environmentally friendly way. the environment.

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