Greening of urban areas: restoring a building site to bring nature back

ReStory narrator: Beate Hölscher

Most urban areas are heavily transformed because natural vegetation is replaced and removed. This is especially true for the Gauteng Highveld, where the highly diverse grassland has to make way for cultivated and often mono cultured exotic gardens.

The average building site is not a joy to behold. The standard practice is that all vegetation and topsoil is scraped off into one huge heap and in this way the site is ‘cleaned’ and prepared for construction. And afterwards homeowners spend large sums of money to bring in fertile soil and plant up the areas again.

It does not have to be this way. When Johan and Beate Hölscher decided to build a house on a pristine piece of grassland outside Pretoria (Rietvlei View Country Estate) they were resolute to do it differently. It seemed a shame to disturb any of the grassland, so they knew that they wanted to destroy as little as possible of the veld, and restore whatever was disturbed in the building as much as possible.

Today, 5 years later, less than 30% of the 1 hectare is disturbed and transformed and they have a cherished garden that is a natural grassland which boasts a diversity of 122 indigenous, in situ species that occur naturally there and were given a chance to resprout and re-establish after the building. Beate is collecting the plants for her private herbarium which records each species.

However, there are always areas on and around the building site which are irreversibly destroyed, and it is on these areas that active restoration was undertaken. Although they tried as much as possible to delineate and restrict activity to the footprint of the house (with chevron tape, building cloth and stern words to the builders) there invariably was more damage than desired.

These damaged areas around the house were planted with indigenous trees and shrubs suitable to the area. A previous stand of wattle trees is the site of the vegetable garden today (the soil having been conveniently enriched by the nitrogen fixing trees) and the area where the sewage system was installed is a mini arboretum. At the bottom end of the property a large wattle tree and disturbed surrounding ground was converted into a natural dam. All the rocks that were excavated for the building site were used in the landscaping, terracing and forming natural rockeries and borders.

Where possible, tufts of grass, bulbs and shrubs that were uprooted were planted into selected areas. But the real magic happened when good summer rains and time brought the original plants back to life, and with it the diversity of insects, birds and reptiles.

It is indeed up to each one of us to play a part in restoring and conserving the precious heritage of our natural veld and soil. And it is not impossible and difficult to make it a lifestyle. It is richly rewarding.

Five important tips for gardening in and restoring grassland:

  • Many species are underground dwellers, and will come back in time, as long as the ground and roots are intact. If an area was heavily trampled, driven on or the surface cleaned, the grassland can recover. An area where the ground was ploughed, moved or dug up will NOT recover, because once the precious living zone of the upper 50 cm is disturbed, it is gone forever.
  • A natural grassland garden needs to feel fire from time to time to retain its natural diversity and structure. We trim the long grass with a weed-eater and then the shorter grass is easier to burn. We burn once in 3 years and in-between we burn fire breaks on the boundary of the property.
  • For planting up the cultivated part of your garden, use indigenous plants that do well in the area. In our area the standard favourites which are waterwise, attract wildlife and are always green include Sour fig (Carpbrotus), Bush violet (Barleria obtusa), Blue honeybell bush (Freylinia), Bulbine, Ribbon Bush (Hypoestes aristata) and Iris species.
  • Keep weeds under control. Disturbed areas are breeding grounds for weeds such as Khakibos, pompom weed and others. Rather scatter seeds of indigenous pioneer plants (such as wilde dagga, Nemesia, wild foxglove, etc.) which will sprout easily and grow without too much pampering.
  • To retain a grassland, trees must be kept under control. Keep the trees in the areas where you want shade and protective cover, but do not allow them to get a foothold in the grassland.

From this…

To this….

Most grassland plants are very resilient and will resprout, as long as top layer of soil with the roots are not destroyed. This Copper leaf (Acalypha angustata) now forms part of the natural garden.