The origin of indigenous plants suitable for gardening purposes on the Highveld will be discussed. The idea is quite simple – use plants in your garden that occurs in Southern Africa that is adapted to our local conditions. Ideally, one should use endemic plants, that is, plants that occur naturally in the surrounding areas. In this regard, we really live in an extraordinary and exciting environment where two major plant communities overlap To understand the implications from a gardening perspective more clearly, let me introduce the concept of Biomes.
Biomes in South Africa
A biome is defined as an area where the vegetation is fairly uniform and adapted to that particular environment. Most of us have a natural “feeling” for this – we talk about the Bushveld, the Karoo, Fynbos etc. Let us look briefly at some of these plant communities or biomes.
The Grassland Biome is found chiefly on the high central plateau of South Africa, and the inland areas of KwaZuluNatal and the Eastern Cape. The topography is mainly flat and rolling, but includes the escarpment itself. Altitude varies from near sea level to 2 850 m above sea level.
In the grasslands, trees are virtually absent, except in a few localized habitats. Bulbs and other plants with an underground rootstock are often abundant. Frosts, fire and grazing maintain the grass dominance and prevent the establishment of trees.
The Grassland Biome is considered to have an extremely high biodiversity, second only to the Fynbos Biome. Rare plants are often found in the grasslands, especially in the escarpment area. Most of these plants are adapted to survive grazing and fire and are therefore well adapted to gardening conditions
The Savanna Biome is the largest Biome, occupying over one-third the area of South Africa. lt is well developed over the Lowveld and Kalahari region of South Africa and is also the dominant vegetation in Botswana, Namibia and Zimbabwe.
It is characterized by a grassy ground layer with disjunct scattered trees or shrubs. The local vegetation may be known as Shrubveld, Woodland or Bushveld depending on the dominant upper layer.
Most of the Savannah plants survive fire, drought and grazing and are therefore also well adapted to gardening conditions.
In our area, the Grassland Biome and the Savannah Biome meet. This implies that many plants from both these biomes are well adapted to our environment. (In practice, it has also been found that plants from the Thicket Biome from the Eastern Cape are also very well adapted to gardening conditions). Where such major plant types meet, other interesting phenomena also occur. There are plants that only occur in this transitional area and nowhere else. (In our case, the most widely known is Aloe peglerae that is endemic to the Magaliesberg).
Obviously, many other environmental factors should be considered before you choose plants for your garden, such as soil type, temperature, aspect and so on, but at least the basket is enormous.
Plants Suitable for Our Area
There are many plants from the three Biomes that can be grown in our area. In later editions, this will be discussed in more detail. What must be borne in mind is that local climate can vary considerably and must be taken into account when plants are selected. For instance, in the central valley south of the Magaliesberg frost can be severe whereas only three kilometers away at the slopes of the mountain, frost is a rarity.
Endemic plants that are well adapted to gardening conditions are the corkbush, Mundulea sericea, common hook thorn, Acacia caffra and the beauty of early spring, the wild pear Dombeya rotundifolia. Plants suitable for our area will be discussed in later editions.
Please tell us some of your experiences or plants that you have grown successfully in your garden.
Dr Johan Wentzel can be contacted at 082 801 1741 for any constructive inputs.