There is more than planting a bunch of native plants to creating a landscape design that has ecological and aesthetic value. This article introduces edge effects in biodiversity briefly while focusing on how these processes can shape our aesthetic vision for our gardens.
Human beings can detect the difference between natural and designed landscapes easily. Where many designers slip when attempting to design a natural garden is by missing the visual cues that speak to us subconsciously. Paying attention to the concept of edge effects in biodiversity helps in designing landscapes that seem more aesthetically natural, if that is one’s goal.
Edge effects in biodiversity refer to the changes in population at the boundaries of plant communities. In natural boundaries, these changes are due to factors such as a change in growing conditions, microclimates, or disturbance (fire, human intervention).
There is rarely an abrupt transition from one plant community to another…there is a transition with overlap of plant species in these boundary areas. Often these edge communities are the most species diverse and valuable places in an ecosystem.
Thinking in terms of tapestry vs. groupings is a useful way of considering edge effects in landscape design. In the natural landscape and our gardens allowing overlap and intermingling of plant groupings is healthy and visually beautiful.
Virtually every small garden has obviously been heavily shaped by human beings. It is the rare homeowner that has the discipline and aesthetic to let nature take its course while providing the growing conditions to actually develop a natural landscape in their front yard (landscape architect and painter Philip Juras is that rare breed who has done exactly this). I signal out Philip as an example because many of his paintings portray the vital edges of plant communities (often created by fire driven ecological processes).
What many landscape designers, landscape architects, and gardeners do is plant perennials and shrubs in groups around the landscape. These groupings may be allowed to spread but much of the maintenance and effort goes into maintaining these groups rigidly, with lots of weeding and pruning.
Commit to chance in the garden…allow borders to drift and intermingle.
Piet Oudulf, a landscape designer whose work is beloved by many, struck at the heart of good design when he said that chance should play a part in the landscape…the idea that plants moving around the garden is a good thing. Piet Oudulf’s most famous landscape design is probably the Highline Park in Brooklyn
Think of the garden as ecology and design on a small scale. Our plant groupings are each a mini plant community. Just as plant communities have edge effects that are rarely rigid, allow the plants in the garden to spread and intermingle. When planting groups, include outliers, one or two of a species set away from the main group but close enough that there is still a passing relation.
More resources for learning about biodiversity/edge effects:
Notes of formal & informal landscape design:
By designing any space we introduce artificiality so far as the ‘natural landscape’ is concerned. It is crucial that the landscape designer have a firm grasp on what the goal is for the design. A formal garden is obviously a product of heavy design work and is often an extension of the structure that visually dominates the landscape (house, office building, etc.). The formal garden features architecture with plants in a very forward way. Natural landscapes tend to be trickier. Is the goal an informal or cottage garden or a full-blown restoration of an ecosystem?