Wildflowers of Polokwane 1
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
The number 1 in the title of this article indicates that I'm intending to write additional articles about the wildflowers of my home town, Polokwane. Indeed, I'm actually thinking of writing a whole book! Strictly, it will cover the region called the Polokwane Plateau. This plateau lies at an altitude of about 1200-1300 m/4000-4250 ft above sea level. It features a unique vegetation that has been called Polokwane Plateau Grassland, Polokwane Plateau False Grassland, and currently Polokwane Plateau Bushveld. Now, indeed the vegetation of this region has in the past had more features of a grassland, but there have always been many trees, though they were widely spaced with large expanses of open grass between them. Recently, because of human influences on the environment, the grassland has been invaded by more and more trees, so that at present it is more of a savannah. The vegetation does indeed vary a lot between different places, with some having more grass and some having more trees, but there's a lot of uniformity. The whole region receives a rainfall of about 500 mm/20" per year, with only some mountain and hill slopes getting a bit more. There isn't really any particularly dry places, though the region experiences a long period of winter aridity, and there aren't true closed-canopy forests on the plateau, although there are good stands of riverine trees, and dense thorny thickets on some hills.
There hasn't yet been a book written about the whole flora of this region, which is why I'd like to attempt the task. We do have wonderful plants here, as you'll see – and also, these plants need our recognition, our awareness, our help. The Polokwane plateau region is a place where much development has taken place and more development is slated for the immediate future. As a result of this development we have already lost much wild habitat in which rare and unique plants are found, and several species are now threatened with extinction.
When my family and I came to Polokwane in 1980, most of the land around our house was wild. We heard jackals calling almost every night. I could be out of my house and within five minutes I was in the veld and seeing birds, amphibians and small mammals like hares and steenboks. I could hike in the grassland for hours and hours, making discoveries like small rocky hills that I could climb and where I could sit enjoying wide views of the countryside, and large marshes where many species of frogs were breeding. As a kid I wasn't as attentive of plants as I am now, but I always appreciated them. I had a special love for trees, seeing as trees, especially big ones, were fairly rare, and their shade a very welcome respite from the burning African sun.
I thus started my plant fascination by learning more about trees. In many nature reserves over here, some trees have little identification plaques on them. We bought tree identification guides also, and soon I knew most of the trees typical of northern South Africa. From trees, I soon progressed to succulents and flowering herbs and shrubs. A large number of books have been written about various different groups of South African plants; many of these I was able to find in our local library as well as in bookshops, and I devoured them (figuratively!). But in the process of all this learning I realized that there is much, much more than has ever been put down in books. South Africa has about 25 000 known species of flowering plants; it is a rare book that can deal with more than about a 1000 of these. There are groups that haven't yet had any decent guide dedicated to them, and there are regions in the country that haven't yet been adequately covered. There must be many plant species that haven't yet been discovered, to boot.
Even more, we know of most plants in South Africa merely that they exist. We don't even really know where they grow. Yes, we know where we found the specimens that we have … but many of them, collected from a certain location, also grow in other locations where no botanist has yet been. It is not at all unusual for botanical explorations to turn up plants far away from the regions we thought they were confined to. And this is good… if a plant occurs more widely than we thought, it means it is less vulnerable to extinction. But at the same time, there are those plants that only grow in very small regions and that are consequently very vulnerable. This, too, we can only determine after much exploration and seeking.
We also don't really know the ecological requirements of most of our plants. That would be, the kind of soil they like to grow in, the kind of temperature range, the rainfall regimen, the amount of sun and shade they prefer to grow in, the other plants that share their habitats, and the animals with which they interact. The latter includes the insects and other animals that pollinate them and distribute their seeds. These are vital to their existence. In turn, they are important for animal species that depend on them, such as the insects that feed on them. While most herbivorous mammals feed on a wide variety of plants, insects are more specific. Some insect larvae only feed on a single genus or even species of plant, or at most on only a few kinds. Thus, they are at high risk if the plants they depend upon should dwindle or disappear.
A specific kind of knowledge about our plants, is how to propagate them. This knowledge would be immensely valuable in helping us protect rare species. Unfortunately for most of our plants this, too, is something we still don't know much about. Many species can be grown from cuttings, which is a most convenient way if it happens to be difficult to find them in flower or with seeds. Sometimes cuttings may only root and grow with special treatments. And then there are many that refuse to grow from cuttings – you have to find their seeds. Which can be hard. And even if you get the seed, sometimes they only grow with very special treatments. Many have hard seed-cases that need to be weakened, by nicking or grinding them. Orchid seeds can only grow in nature in the presence of certain fungi … humans can only grow them on special nutritive mediums under sterile conditions. Many grassland plants have seeds primed to germinate directly after veld fires; these may need to be exposed to smoke and heat if we wish to grow them.
So it has been a source of great anxiety to me to see how much wild plant life has been and is being destroyed over here. We are losing not only beauty and ecological value, we are also losing knowledge. When something is no longer there, then you can learn nothing more about it. That goes for species and also for ecosystems. The environment is so much changed that it is unlikely that many of these plants are still existing under anything close to the natural ecological situation they evolved in. They are hanging on under unnatural conditions; they may no longer be able to maintain their populations. Indeed I've seen populations dwindle and disappear even in places where they receive nominal protection.
It is therefore with a sense of urgency that I am exploring the regions that are at least semi-wild and that remain here around Polokwane. Many of these places are just small patches of veld surrounded by streets, residential areas, businesses, farms, mines and the like. Even these patches experience heavy stresses: people walk through them, cows and goats graze in them, they're sometimes burnt frequently, people even dump their rubbish in them. The amount of rubbish just lying around the environment here can be staggering. Rubbish can attract things like rats, which then also gnaw and damage the vegetation.
But incredibly, many plant species still hang on in these patches. The photos I share here, were mainly taken in such small patches of veld. Indeed, those are where most of the diversity is still found. The only really well-protected place here is the Polokwane Nature Reserve, and it features only a small sample of the vegetation, with many of our rare and unusual species not even present in it. So I'm also working to catalogue where you can find what. As you can see, we have some amazingly beautiful and interesting species here. I'm hoping to interest people in the more charismatic ones; if the places they grow can get protected, then we can also preserve the less charismatic, but still ecologically important (as absolutely all species are) ones that grow in the same spots.
The plants you see here, are all essentially grassland plants. Contrary to what people might conclude, in grasslands, grasses actually constitute only a small part of the plant diversity. In grasslands, many species of plants have subterranean bulbs, tubers, corms or rootstocks. They may die back to ground level in winter, resprouting surface stems with leaves and flowers in the spring. Examples are the Gladioli, Gnidia and Hypoxis. A special kind can be called an underground tree, for it may have huge woody 'branches' stretching underground for many meters, but with only tiny above-ground twigs. Here you see a prime example, an Elephantorrhiza or 'elephant root'. Some plants are annuals, dying every winter so that the next year's plants all have to grow from this year's crop of seeds. A few hardy herbs and shrubs are perennials. Succulents like the Euphorbias here survive the dry winters by storing water in their stem tissues, and survive grass fires by firstly not being very ignitable, and secondly by often growing in rocky crevices, where the fire can burn over and around them without harming them. They protect themselves from grazing animals by a poisonous sap and, in some species, by sharp thorns. Trees and shrubs like the Corkbush, Mundulea sericea, that grow in open grassland, are protected against fire by having very thick, corky bark around their lower trunks. An interesting group of plants are the parasites, such as Striga elegans. These plants 'steal' nutrients from the surrounding grasses, by way of underground specialized root-like structures that penetrate the grass roots. Striga, at least, needs to do this as a young plant, but when it grows up, it can manufacture some of its own food.
We have many plants here with beautiful flowers. They are mainly adapted to pollination by birds or insects. Wind-pollinated plants have comparatively dull flowers, but some of them are also fascinating. Finding flowers in the veld demands expert timing. The majority of plant species flower over a brief period in the spring and summer. Some flower only for a period of a few days. This is often the case for plants that are stimulated into flowering after grass fires – a strategy that helps in many ways, making the flowers more easily seen, and offering an 'open' landscape with lots of nutritious ash for their seeds to germinate in. Then there are also those plants whose flowers are only visible at a certain time of day – or even at a certain time during the evening or night. Outside of these periods, the flowers close up. There are a few species that are long-flowering, even to the extent where you can see flowers on them over most of the year. A small number of species flower predominantly in the winter, notably some of the aloes. The nectar of these provide an essential source of nutrition to birds and other beings over the dry months when other kinds of food are very scarce.
Another factor in flower visibility is size. The photos you see here are all about the same size; in the veld, however, some flowers are large and highly conspicuous, while others are tiny. Of the flowers shown here, the Pterodiscus and Gladiolus flowers are large and easily seen, while the Asystasia has flowers just a few millimetres in diameter. Many times you will have to bend or crouch down to get a look at the flowers … but this will be rewarding, as some of the smallest flowers are also some of the most exquisitely beautiful.
This has just been a brief introduction to the flora of the region. I will in my next article speak more of some of the very special plant species found around Polokwane.