– Text by Marijke Honig
ALL green areas – whether planted landscapes, wild areas, or a road verge with weeds – contribute to the urban ecosystem. They are vital to our well-being: green areas produce air for us to breathe, they filter pollution, absorb storm water and reduce flooding, purify water and maintain a pleasant temperature. Without sufficient planted areas and infiltration – due to the many tarred and paved areas, and reflective surfaces – the city heats up. This is known as the urban heat island effect: pollution levels rise and our quality of life decreases. On summer days, especially when there is no wind, the raised temperature is already evident in the City Bowl, which is a few degrees hotter than the suburbs.
Gardens form an important part of the urban ecosystem and are not a luxury: they are a necessity. Green areas provide habitat for wildlife and are good for our well-being. Please do not feel guilty about gardening! We encourage anyone with access to alternative water sources, such as borehole or grey water, to use it responsibly to help maintain the urban ecosystem. Furthermore help spread awareness of its value and the importance of permeable surfaces for infiltration of rain. This will make a positive difference.
Some simple ways you can help preserve the urban ecosystem:
- Do not remove successful plants. Consider valuing plants for their resilience and ecological function, in addition to personal preference. A thriving common or weedy plant is better than nothing green at all!
- Mulch all planted areas with a 5 to 10cm thick layer of mulch. This dramatically reduces water loss from the soil surface and keeps it cool. Organic mulches such as chipped wood and leaves are best, as they feed the soil and your plants.
- Keep areas planted, not paved. Consider how important it is for rainwater to infiltrate the soil: this is important for recharging groundwater (and good for trees) and keeps the ambient temperature down. Avoid hard surfaces where possible and use permeable paving when a hard durable surface is required.
- If you do have a borehole, water deeply and infrequently. Mimic a good rainfall event of say 50mm and really saturate an area, with water penetrating at least 50-60cm into the soil. You may only need to do this every 3 to 4 weeks.
Trees reduce air pollution in the urban environment, absorb CO2 and shade roads to decrease heat sink aspects. (Clare Burgess)
Wild green belt / city parkland. (Marijke Honig)
Low maintenance road verge with no irrigation. (Marijke Honig)
Two local resilient plants species – Hermannia pinnata and Senecio crassulifolius. (Marijke Honig)