Climate-Resilient Gardens
Introduction: green urban ecosystems and climate resilience
As a consequence of the climate crisis, extreme weather events occur more frequently and with more drastic impacts across the globe. For instance, droughts, heat waves, wildfires, heavy rainfall and storms have haunted Portugal in the past years – and are likely to increase in the future [1]. Due to this, we have to carefully think about how to design and adapt our built environment to be as resilient as possible to these new challenges. One of the many important areas of transformation towards more resilience lies within our urban space.
An important base for resilient ecosystems within the urban realm are thoroughly-developed planting concepts for green areas. We refer to them as “climate-resilient gardens”. Through selecting a variety of climate-adapted or climate-tolerant plants and arranging them in a certain layout together with the unsealing of surfaces, manifold advantages can arise: rehabilitation opportunities for the soil, cooling of the environment to mitigate the heat island effect, biodiversity increase i.e. through the accommodation of endangered insects, permeable surfaces for groundwater infiltration/replenishing, and the ability to resist storms and erosion. Altogether, they contribute to the resilience of cities in extreme weather and – as a positive side effect – they oftentimes require comparatively low maintenance efforts.
While those gardens have the potential to be rich and healthy ecosystems, the status quo of a typical public urban square in Portugal – but also in many other places – offers little climate resilience. The public space in Portugal is characterised by a high degree of soil sealing, little shade, limited plant variety, and oftentimes dried out trees and plants. In some places, grass can be found, yet planting it as a monoculture does not store as much carbon compared to green patches with a plant variety. This is because low diversified vegetation/monocultures do not provide much to increase the microbe population in the ground [2] which contributes to the number of soil nutrients. Furthermore, while trees and grass store about the same amount of carbon in the soil, trees store almost 20 times as much carbon in the vegetation itself. Luckily, our partner, the Municipality of Esposende, is familiar with those realities: they have already adapted their greening interventions towards more variety and self-sustaining plants.
Making public space more resilient: The case of Apúlia
We took it upon ourselves to turn certain parts of a public space into small climate-resilient gardens: as a part of our recent public space renovation project in Apúlia, we extended and regenerated six existing green areas with the help of Maria Catana from Húmus Vivo. Húmus Vivo is a Portugal-based project aiming to spread regenerative soil practices, through educational hands-on practices. Currently, Húmus Vivo is engaged in a permaculture project, together with our partners in Greece, Southern Lights. Maria’s approach is particularly attentive to the importance of breaking the wrong assumptions of tidy and highly-choreographed gardens, with a centred tree amongst a neat, freshly-cut grass patch. These gardens in fact tend to have lower carbon sequestration capacities than many ascribe to them.
Gardening Interventions
In Apúlia, in an effort to push the urban realm closer to nature and to encourage a stronger connection to wildlife, low-maintenance edible plants and perennial species were planted around the American sweetgum trees and in the picnic area in Zone 3 (see map below). We chose species that do not require a large amount of water, being adapted to the local conditions. They will allow for the reproducing a small-scale forest in a circular plan and providing a rich and healthy soil. A variation of aromatic plants (rosemary, cilantro, thyme) as well as vegetables and fruits (lettuce, strawberry, kale, pepper, beetroots, pumpkin) are surmounted by a bush (laurel and pomegranate) and a tall fruit tree (apple and fig tree), creating a variety in plant height and symbiotic effects amongst the different species. In accordance with the local conditions of Apúlia, succulents were integrated in the planting, as they have the capacity to withstand longer periods of drought.
Map showing the three zones of intervention in Apúlia
A similar approach was taken for the planting of the new flowerbeds created among the already present trees in front of the football field (Zones 1 and 2), improving the quality of life of the community and the local biodiversity through resilient gardens. As the superficial roots are vital parts of the root system of a tree, the stress induced by waterproofing and lack of space near the trunk caused the roots to spread outwards seeking water and nutrients to subsist, but lifting the pavement in the process. The solution for the improvement of the ground is composed of two action fronts. First, we opened the area around the trees, so that their needs could be met through the superficial roots in a breathable surface. Second, we proceeded to the roots and branches. By increasing the flowerbeds considerably, the tree is expected to recreate its surface root network in open spaces and no longer interfere with the pavement. With the help of residents, these new beds were then filled with biodiverse vegetation, resilient and adapted to edaphoclimatic conditions.
All the plants that were used in Apúlia are aromatic/medicinal plants or endemic species found in Portugal. They are characteristic of coastal areas, especially of dunes: they adapt well to sandy areas exposed to a lot of sun and do not need much water. During cold nights, they are able to take advantage of the humidity from the air: when there is a high difference of temperature from the night to the day, evaporation occurs which is then trapped by leaves resulting in condensation and eventually droplets that go back into the ground. The mix of vegetation chosen supports the existing trees, contributes to the infiltration capacity of rainwater into the soil (dense draining root system), provides various medicinal and aromatic uses for the community (lavender, sea wormwood, mediterranean saltbush, sea fennel and others) and lastly contributes to biodiversity in the urban context.
Findings
The resilient gardens were revisited half a year later, in the beginning of February, to assess the plants’ growth and do some maintenance. We mapped the different conditions of the existing plants and a list of those that survived best. Based on that, we took decisions on which species to plant again and which others we could now introduce. Finally, the soil was covered with a layer of about 4-5 cm of pine bark to ensure that the humidity of the soil was maintained.
Plants planted in August 2022:
- Achillea millefolium (Yarrow),
- Limonium ovalifolium,
- Tagetes erecta (Tagete),
- Hipericum perforatum (Erva de São João ou Hipericão),
- Myrtus Communis (Murta),
- Crithmum maritimum (Funcho do mar),
- Malcolmia littorea (Goivinho da praia),
- Artemisia maritima (Artemisia),
- Rosmarinus officinalis (Alecrim),
- Thymus vulgaris (Tomilho),
- Aloysia citrodora (Lúcia-lima),
- Atriplex halimus, (Salgadeira),
- Lavandula angustifolia (Alfazema),
- Glaucium flavum (Papoila Das Praias).
Plants planted in February 2023:
- Rosmarinus officinalis (Rosemary),
- Thymus pulegioides (Thyme),
- Santolina etrusca (Etruscan cotton lavender),
- Achillea millefolium (Yarrow),
- Helichrysum italicum (Curry plant),
- Iberis ciliata,
- Fragaria vesca (Strawberry plant)
When returning to the site, we also did some other critical observations so that we could conclude some (preliminary) Lessons Learned:
Firstly, what we had not thought about when designing the gardens were the dogs that would “do their business” amidst the plants. Dog excrement adds an extra portion of nitrogen and phosphorus to the soil. In small amounts, that can have fertilising effects. However, in residential areas, dog poop comes in high concentrations, resulting in high levels of nitrogen. That again favours certain plants that can cause the extinction of others [3], causing ecological imbalance. A small barrier like a fence together with signs asking dog-owners to keep the dogs out of the flower beds could tackle this issue. The sign could furthermore explain why dog excrement is harmful for plants, as many people might not be aware of the above named facts.
Secondly, since there is no single person or organisation in charge of keeping up maintenance efforts, it is hard to ensure that either the community or the municipality is sustainably engaged in taking care of the space (watering, picking up trash and dog excrement from the beds, pruning trees, etc.). The fact that looking after the plants is an “unpaid favour” probably influences the municipality’s and neighbour’s prioritisation of it. To face this challenge, a person living close by or running a business there could be named the person in charge to let either us or the municipality know that the garden needs maintenance. This factor is though very variable on the type of community surrounding the intervention, and the work developed with this community.
Thirdly, we observed that the space is more exposed to wind than we had thought, leading to harm on the plants and trash ending up in the flower bed. For these two issues, the community and authorities could and should make an effort to gather and organise for two annual days (spring and autumn) to join forces in cleaning up the space and do gardening activities together.
Garden beds that were transformed by planting climate-tolerant and climate-adapted species
Involving the community
In order to not only increase the biodiversity of the site but also engage the neighbourhood in the process and respect their interests, the residents were invited to participate in greening the space, fostering knowledge transfer on climate resilient vegetation and contributing to their acceptance of our actions. We organised a planting workshop and invited them to bring plants they would like to see (and harvest) in this public space. In fact, when we approached the site for the first time, we had already stumbled upon some active gardening initiatives.
For instance, a resident called Emidio had already informally implemented vegetable patches in a bordering fallow area that belongs to the municipality. He cleaned the plot and started gardening: through his actions, Emidio transformed dry land into what serves as a communitary vegetable garden, including tall cabbage, physalis and lettuce among others. We wanted to make use of that local knowledge and gardening enthusiasm. Therefore, fostering his initiative by designating this space to be a formal space for a community garden was essential. Having the municipality’s support, we planted herbs, vegetables and fruit in this plot – for the community to care for and eventually harvest and consume. Emidio helped by lending tools and his labour. After speaking to him and to other inhabitants, we realised this would be an ideal picnic area, due to its green environment and its quiet location. Together with Emidio, we removed the remaining garbage occupying the space and built a spacious table with benches for sharing meals.
We noticed that the residents’ participation provided them with a certain sense of ownership and responsibility over the public space that is also required for future care of the plants. The effect of the neighbourhood’s willingness to maintain the space makes the garden even more resilient – and likewise, gardening contributes to the community’s health and physical activities [4].
What we learned
Similar to other things we have done, we considered this an experiment. Certain plants were in a bad state after half a year, while some others were thriving. The most “successful” plants were Artemisia maritima, Yarrow, Rosemary and Glaucium, that can be often found in the primary and secondary dunes of the region. In this experiment, we realised the importance of site-specific information: small things like wind corridors, dogs, prior activities etc. can influence the condition of your garden massively. Furthermore, we see positive effects in developing a resilient garden in a participatory manner. Through the ways that neighbours were involved, we could increase their sense of responsibility over the garden, so that they now harvest but also take care of the garden. We therefore recommend in-depth conversations and knowledge transfer with neighbours or other people who are familiar with the site.
Interview and reflection with Maria from Húmus Vivo
CC: How did you become familiar with the concept of a “resilient garden”?
Maria: Although I am sure that the term exists across the globe, it was actually what I came up with to describe to the public what we wanted to implement in the public space of Apúlia. This term came out of a necessity to simplify the communication of our intention.
What does a climate/resources resilient garden mean to you?
Imagine a garden: it can be your lawn, it can be a garden outside your work, just imagine any planted space. Now think of it like a garden that doesn’t need much water, much maintenance or fertilisers, pest controllers, etc… Does it seem impossible? Actually, it isn’t! We can create this kind of garden, by placing elements in a way that preserves natural processes and serves the purpose for which it is being designed for. The resulting garden is resilient in the sense that it can withstand extreme weather events (to a certain extent), and better adapt to the more frequently changing external conditions.
Why do you think it’s important to develop this kind of action rather than conventional greening?
Even though the list can be infinite, it is all very connected to the health of the soil. That’s because healthy soil can infiltrate and hold more water, improve drainage of the landscape, and sequester more carbon from the atmosphere. What seem to be small improvements at first, result in the creation of the so-called green corridors, a healthy hub for bird migration, pollinators, and other insects that play a major role in pests and disease control. By improving the life and structure in our city soils, we diminish the impermeabilization factor that is affecting so negatively the small water cycles and we allow for the replenishing of the water we take from the ground, which has a direct impact on desertification and climate change.
This kind of action also has an important social factor by providing a community sense and responsibility over the involvement in its installation and maintenance. It reduces social inequality through nature connection, as unfortunately, green spaces filled with life are not accessible to all neighbourhoods, and actually, observing a butterfly, a flower, or the leaves changing over the seasons, should not be a privilege. Ultimately it gives a perspective to the inhabitants where food sovereignty is considered, as well as food nutrition and awareness!
Through conventional greening of public spaces, most of these factors are put aside, as the result is usually of little ecological or social value.
Is it relevant to intervene at such a small neighbourhood scale? Can a small-scale project still have an impact on the bigger ecosystems?
When speaking of urban gardens in particular, unless policymakers take broader actions to change the way green areas are managed in cities, the solution passes with many small projects to have a global impact. Referring back to the green corridors that I have already mentioned, are a great example of how many small actions can have a crucial impact on wider ecosystems. By creating several small hubs for birds and insects close to each other, safe migrations, seed transportation, and other relevant natural services are permitted to happen.
I also believe that the more examples we create and approach municipalities with, the easier these proposals will be accepted and set in motion. First small projects like this need to be implemented and tracked so that bigger projects can attract and benefit several stakeholders.
There is a sentence often quoted in the permaculture movement that I really appreciate: “grow food, not lawns”. Why not apply it in the urban context?
How important is the collaboration of local communities for the sustainability of the space? (ecologic, economic, maintenance)
Humans are simply part of nature. When we create a system that intends to mimic natural processes, we must not forget the action of the human being: it can be an amazing tool to speed up processes and maintain an overall balance in the system. Of course, if the humans decide they don’t want to be part of this system, the rest of the fauna and flora will survive and adapt well, but there will be a missing piece. Therefore, to answer the question, the collaboration of local communities is of high importance when considering the overall sustainability and lasting of the space.
When it comes to maintenance, by being aware and caring for the space, the inhabitants can help the garden thrive, especially when using the plants for tea, plasters, or even to eat (simple pruning action), when being conscious of not throwing trash and stepping too much around planted areas, and when interfering in the space in order to maintain its beauty and vibrant life.
There is also an advantage in taking care of the gardens from an economic point of view since greener areas bring added value to the neighbourhood, and the local commerce can benefit from an improved outside space.
Would you like to explain the intervention you conducted in Apúlia (Canteiros Regenerativos and Jardins Resilientes)?
The intervention led by Húmus Vivo in collaboration with Critical Concrete in Apúlia was divided into two action phases carried out with inhabitants and other participants in the format of educational workshops. Both of these actions come with the intention of rehabilitating the existing space to better accommodate the social and ecological needs in place.
Canteiros regenerativos (Regenerative garden beds) were designed to cover the need of shading the newly implemented table for social gatherings in a space where we wanted to promote individuals to act collectively and appropriate the remaining soil to create vegetable community gardens. To encourage them to do so, we created what I like to call two tree nests where we imitate a small forest. The main central pieces on these nests are fruit trees for the community to enjoy, as well as the lower layer bush/tree that is placed below the taller tree. Surrounding these elements in a circular design, many perennial aromatics and annual vegetables were planted inside a nest of organic matter (branches, leaves, and compost) that will serve as food for the soil during the upcoming years! All of these introduced plants are edible.
Jardins resilientes (Resilient gardens) was the action led to enhance the large area where around big deciduous trees the soil was mostly covered in cement and bricks. The pressing conditions made these trees lift the bricks around them in search of surface water, and ground permeabilization. The resulting situation was not pleasant for either the residents or the trees, so we set in place a solution that accommodates both. The trees got bigger spaces underneath where now companion plants live and soil is being restored, and the humans have a flat surface to walk on since we pruned the roots that were too long and rebuilt the floor on top. Most of the plants introduced have a medicinal/aromatic value and are adapted to the local conditions.
What are the main threats to the success of such intervention and which measures are you taking during the design phase to prevent them? (i.e. trash, dog pee, etc)
The main threats are very important to identify when designing a project. It was by making a clear assessment of the local conditions that we were able to, for example, understand that during winter, strong cold northern winds carrying salt damage some plants in the surroundings. That immediately ruled out some of the plants we had in mind for the type of soil and indicated weather conditions. Instead, we not only chose plants that are more likely to withstand strong salty winds, but we also planted on the north side some strong fast growing bushes that can protect more delicate ones planted south from them.
Even though this garden is located in the North of Portugal, where the summers are milder, we took much thought into designing a system that could go through longer droughts, since these events are increasing in frequency, and there aren’t always sufficient municipal resources to maintain all of the watering needs of the existent green areas. For that purpose, we introduced adapted species to the local conditions, that could grow wild around the beach or in the forest nearby, played around with stratification (sunlight filtered by the leaves of the several plants), covered the ground with organic matter, and focused on building up topsoil, which supports the water holding capacity of the soil, making water available to plants for longer periods of time.
Another major threat to the long-lasting life of these gardens is the mistreatment by people, which is why we thrived in involving the community since day one, as to nurture that important sense of belonging that I have mentioned before! Another more practical solution that we implemented throughout the design phase was to build small walls around the patches where possible, and plant stronger bushes on the border lines, which can prevent overstepping and compaction!
What are the first steps we need to take to design a resilient garden?
Observing the space, the conditions, and the needs are the first assessment that needs to happen in order to design an effective and useful resilient garden. When envisioning the outcome, natural conditions should be taken into consideration as well as the evolution of the system. I started by understanding the specific weather conditions of Apúlia, the sun exposure throughout the different seasons, the existing type of soil, and the challenges of implementation, such as future maintenance and watering availability in summer, for example. Then a social evaluation was put in place through interviews with the residents, the vision of the project on Critical Concrete and the municipality side, as well as what could an improved space bring out to the community that would fit their lifestyle and wishes.
With all of this information gathered, the next important evaluation prior to the actual design phase, was to assess the different species that appear spontaneously in local ecosystems, versus what is available in the market by contacting local hortos [nurseries] and different seedlings providers, in order to have the full picture of the possible elements more suited to integrate.
What are the most basic principles (like a little recipe) to refer to when designing a garden?
Part of Húmus Vivo’s mission is to change the lenses through which we see life in the soil and not only realise its existence but also understand how intertwined the health of plants (and our own) is with the health of the immense ecosystem that lives within the soil. From experience and passion, I can say that whenever designing or attending a garden, if we focus on enhancing and nurturing the microorganisms present in the soil, we are already doing most of the work. Nurturing the soil is done by adding compost (not only underground but also near the surface as a multiplier of microorganisms), covering it very well with organic matter (a good 5 cm of straw, branches, leaves, grass clippings) that over time decompose and feed the soil population, as well as adding inoculums such as compost tea or mycorrhizas when possible.
Throughout the several phases (assessment, implementation, maintenance) don’t forget the following permaculture principle “Observe and interact!”. Constantly observe what is happening around you, how is your system adapting to the provided conditions and how is it evolving. Your interaction must come from an informed, intuitive and experimental point of view: don’t be afraid to try small changes and see how it plays out!
References
[1] Teixeira, C.P., C.O. Fernandes, and J. Ahern. 2022. ‘Adaptive Planting Design and Management Framework for Urban Climate Change Adaptation and Mitigation | Elsevier Enhanced Reader’. Urban Forestry & Urban Greening 70 (127548). https://doi.org/10.1016/j.ufug.2022.127548.
[2] Piotrowski, Janis. n.a. ‘Less Lawn, More Trees Can Make Your Yard a Better Carbon Storage Site’. Talahassee Democrat, n.a. https://eu.tallahassee.com/story/life/home-garden/2021/04/08/less-lawn-more-trees-make-yard-better-carbon-sink-storage-climate-remedy/7133933002/.
[3] De Frenne, Pieter, Mathias Cougnon, P.J. Geert, and Pieter Vangansbeke Janssens. 2022. ‘Nutrient Fertilization by Dogs in Peri-Urban Ecosystems’. Ecological Solutions and Evidence 3 (e12128). https://doi.org/10.1002/2688-8319.12128.
[4] Caperon, L., R.R.C. McEachan, C. Endacott, and S.M. Ahern. 2022. ‘Evaluating Community Co-Design, Maintenance and Ownership of Green Spaces in Underserved Communities Using Participatory Research’. Journal of Participatory Research Methods 3 (1). https://doi.org/10.35844/001c.35632.
