WILLIAM BURCHELL Travels in the Interior of South Africa, 1822, nearly a century before the Garden’s foundation, and some two centuries before it reached its present state of development
In the shadow of Table Mountain The Overberg Pincushion Leucospermum oleifoliumfronts the Garden’s sweeping, rugged mountain backdrop. The first garden established at the Cape in 1652 was situated close to the stream that flows off the north-facing slopes of Table Mountain. We have already referred to the Company Garden in chapter 1. It succeeded as a source of vegetables for the growing colonial administration, but never developed into a true ‘botanic’ garden. The reason is simple – it was built on the wrong side of the mountain.
Kirstenbosch National Botanical Garden Map Main Cities Photo Gallery
The choice of Kirstenbosch was motivated by the sheer grandeur of the site. There is no evidence to suggest that Harold Pearson did a careful site feasibility study, based on the multiple criteria that are now considered before proposing the establishment of a new botanical garden. He did not consider geology, soils, water, habitat diversity, ease of access or ‘stakeholder’ opinion. He simply knew that ‘this is the place’.
How fortuitous that his choice fulfilled all the key elements critical to the success of a modern botanical garden – a century ahead of his time. Here, in the shadow of Table Mountain, lying on shallow, rough, acidic sandstones, deep granitic clays and peaty alluvial soils, with three permanent streams fed by heavy winter rains, was a site par excellence for a garden. On east- and northeast-facing slopes, drenched by the morning sun rising over the distant Hottentots Holland Mountains, the site cools off early in the afternoon as the sun disappears behind its mountainous ‘garden wall’.
Since the rugged sandstones of Table Mountain were laid down 540 million years ago, the Earth’s continents have drifted across the globe. The ancient Pangaea split into Laurasia and Gondwana, and Gondwana, in turn, separated into Africa, South America, Australasia and Antarctica.
The most striking feature of Kirstenbosch is the sweeping, rugged mountain backdrop to the soft verdure of the Garden. The geological history of the site is long, complex and all but hidden to the visitor by a deep layer of rocky debris that covers the lower slopes of the natural basin in which it is sited. Only a simplified summary of the Garden’s 700-million-year evolution can be given here. The Garden’s oldest rocks are from the Malmesbury Group. These are metamorphic rocks formed by the compression of sediments deposited in deep marine basins. They were formed between 700 and 560 million years ago.
Tens of millions of years later – about 540 million years ago – violent disturbances at great depths caused the rocks of the Earth’s mantle to melt into a viscous magma, which intruded into the overlying Malmesbury and other systems to cool, solidify and crystallise at depths of several kilometres. This process formed the Cape Granites, large exposures of which are found around the Cape Peninsula, most prominently at the Boulders penguin colony. In Kirstenbosch, granite soils support the Silver Tree grove near Rycroft Gate.