This has been one of the most interesting projects I have worked on for a long time. In the heart of Johannesburg, screened of by some ancient oak trees, is one of Africa’s greenest houses, in every sense of the word. The project won the Enviropeadia eco-logic Innovation award this year for pushing boundaries in green architecture. The design of the house and garden took almost 2 years to complete, with the architecture by Kenneth Stucke with the landscape design by me.
The brief from the client to the architect was that the house should be independent from the town council, providing everything it needs for itself. The brief to me was to create a garden that is wild, reflecting a typical natural high-veld scene, attracting as many birds and wildlife as possible. A wetland had to be added to clean the grey water even further that exits through the filters systems, and all the subsoil drainage water and paving runoff had to be caught up and stored in a natural looking storage dam with a capacity of 60,000 liters that we would use for irrigation purposes.
The previous existing house on the property was soft stripped and all re-usable material was given to charity, with the remaining mortar elements used as backfill to the new house. Strict controls prevented any soil contamination, and all products used on site had to be low in toxicity and VOCs.
The new house has three chimneys and each have a evaporative cooler on top, which pushes air through a wet medium. As the hot dry air passes through the wet medium, the water evaporates, pushing cool moist air into the openings all over the house. The stone chimneys are mostly covered by a metal screen, and these screens are planted up with creepers and have atomizer sprays inside, so the cool moist air falls down from the misters and cools the areas of the house that open to the outside.
When it comes to the gardening side of the project, I made use of mostly South African plants, but there were a couple of exotics in the garden, such as wild basil, artichokes, and gaura.
For the most part the house is enclosed with greenery, and this was done with creepers planted in massive planters all around the house. The purpose of the creepers is to cool down the house in summer but to also allow the sun in during the cold winter months.
Creepers were carefully selected for their density, growth pattern, color, and being deciduous or evergreen, and then placed so we would have amazing color on the entertainment veranda, evergreen creepers to block the sun from certain areas of the house, and also deciduous creepers that would allow the sun into certain rooms in winter. For aesthetics a vertical garden was established on the southern side of the house.
The grey water goes through a 2 phase digester system and, after the filter system, falls over a rock face to oxygenate the water flowing through a wetland into the storage dam. Indigenous fish species and frogs were introduced into the wetland area and dam.
When designing wetlands there are such a enormous range of plants that we can use, and each one more interesting than the next, so to choose the ones that would fit the garden was such a difficult task as I wanted all of them! In the end, one of the plants that I used in this wetland garden was Typha minima, such a cute little variant from the big Typha capensis (bullrush).
I also used Cyperus papyrus, common I know, but they do the job so well, and it doesn’t take long for them to be full of birds nests. They tend to take over, so a great alternative for an less aggressive grower is Cyperus ‘Nana’ or Cyperus papyrus ‘Little Dwarf’ each reaching about knee high. I love my grasses and luckily the highveld is mostly savanna, so Eragrostis curvula, Setaria megaphylla, Juncus effusus and Aristida junciformis were some of my favourite ones to use.
What makes this project so unique is that everything is co-dependent on each other – a small eco-system that depends on every element to be in good working order. The waste water system supplies the irrigation system, and provides the nutrients for feeding the plants, and the plants have to be healthy in order to provide the comfort and quality of the internal parts of the house.
And as the plants mature the system will only improve with time, rather than mechanical solutions that get weaker with time.