Another flower that is flourishing in the neglected historical cemetery in Grahamstown is the Vinca (Catharanthus roseus).

Apparently originating from Madagascar, these tough plants seem to flourish sans care in our hot and dry conditions. Thus it is no surprise that it is known as Kanniedood (cannot die) in Afrikaans. Its toughness and ability to seed itself and flourish anywhere has also earned it the moniker of ‘graveyard flower’ in some parts of the country. Another common name is Rosy periwinkle.

These flowers were most likely introduced as a useful ornamental plant – who would turn down flowers that bloom in the drought – but, like so many ‘imports’, has escaped beyond garden borders to become particularly invasive in KwaZulu-Natal, Mpumalanga and Limpopo. So widespread is this flower that it has become naturalised in practically all tropical countries.

I clearly recall these flowers growing ‘wild’ in our garden in Mpumalanga when I was a child. It was one of the few flowers my mother did not mind me picking to decorate the various fairy gardens I created in between the roots of some of the trees.

The flowers are pollinated by butterflies and moths. Seeds tend to be dispersed by ants, wind and water.


The first house we moved into on arrival in Mmabatho, Bophuthatswana, had been plonked onto the semi-desert sand. All the houses there were newly constructed from bricks and the garden areas had been surrounded by a wire fence. The winds howled, and dust storms regularly swept through the area, whipping up the sand loosened by the many construction projects that were involved in the process of starting a new town in the veld. We tried growing a patch of lawn, carefully watering it and marvelling as the kikuyu grass began to spread over the hot, dry sand. Then we watched in awe as the entire ‘lawn’ was carried away by harvester ants! A row of tall, sturdy marigolds was eaten by goats. Gardening there was obviously going to be a challenge.

A group of us decided to tackle our respective ‘gardens’ in earnest and drove to the nearest nursery in Lichtenburg. A neighbour strongly advocated purchasing rosemary on the grounds that “it is hardy and I have grown it everywhere we have settled.” She and her husband had indeed lived in India and various parts of Africa in the course of his work, and so rosemary made its way into my garden too – and I have always grown rosemary wherever we have moved to.

This is not about rosemary though, but the Spanish Broom (Spartium junceum) which – given the harsh conditions we were faced with – the helpful people at the nursery recommended to us. All four of us purchased more than one of these plants and duly planted them in our respective gardens. They proved to be tough and their fragrant bright yellow flowers delighted us from about August onwards. In the Eastern Cape they are still in full bloom during December.

The Spanish Broom, as its name implies, is a native of the Mediterranean region of Europe, was imported here both for ornamental purposes and, interestingly enough, for the control of erosion: fast-growing, tough and pretty – all qualities gardeners look for when starting a garden from scratch, particularly in an inhospitable environment. What we didn’t realise at the time is that this would become an unwelcome invasive species that has proved to be particularly problematic in the Eastern and Western Cape, Gauteng, and Mpumalanga.

As attractive as they are when in bloom, the Spanish Broom is now listed among the most problematic weeds in South Africa. Given that it is estimated they can produce up to 12 000 seeds per plant, it is not surprising to learn that they tend to block light and use up water required by the indigenous plant species. The plants are unpalatable to both domestic and wild animals and the large stands of them obviously reduces available forage. These are not thoughts that cross one’s mind when starting a garden and – at the time – were certainly not expressed by the enthusiastic sales people at the nursery!

The Spanish Broom has been declared a Category 1 plant, which means they may no longer be grown anywhere in South Africa. Gardeners are expected to remove them and nurseries may no longer sell them. So much for laws: unless they are vigorously implemented the march of the Spanish Broom will continue unabated – here is only a small patch of the swathes that have established themselves along the disused railway line cutting through the bottom end of our suburb.


In these end days of winter when most of the veld is covered with the grey-brown or faded yellow of grasses that have lost their seeds, become brittle and are – like us – waiting for the first spring rains to bring forth green shoots, any bright green leaves stand out like the proverbial sore thumb. While a host of trees and shrubs in South Africa are evergreen, we are familiar with them; with their shape, their leaves and their colour. What stands out are plants like this one that do not belong. The Castor Oil Plant (Ricinus communis) is a shrub with waxy stems and large star-shaped leaves with serrated edges. This is another invasive alien that I learned from early childhood to keep well away from for it is toxic. In fact, those reddish stems (to me) serve as a warning not to fiddle with.

The Castor Oil Plant is thought to have originated from the tropical parts of Africa and, as with other alien invasive plants, they have in the past been grown for their ornamental qualities as well as on a commercial scale here. The problem is that escapees have become wide-spread weeds that thrive in the disturbed soil along the edges of roads and open land as well as along water courses. There is one growing to the right of  the make-shift ladder which is next to a river in the following photograph.

The spiny fruits develop on an erect spike. Although castor oil is extracted from the seeds, they should on no account be eaten! The seeds are highly toxic, especially for horses, although it is interesting to read that livestock are able to ingest the leaves without any ill-effects.

As a declared invader plant, it must be eradicated if found growing on one’s property.



Jacaranda trees have been growing in South Africa for so long that most people regard them as being indigenous. That they are not, although the Jacaranda has been a beloved naturalised plant citizen, from the time it was introduced from South America in the early nineteenth century. Jacarandas (Jacaranda mimosifolia) have been planted by municipalities all over the country since then, thanks to their beautiful mauve flowers that more than meet the criteria for ornamental purposes. The most prolific plantings are surely in Pretoria, where it has been estimated that over 70 000 Jacarandas are growing – no wonder it is known throughout the country as Jacaranda City!

A number of these trees grew on the campus of the then University of Natal in Pietermaritzburg, covering the lawns and paths with a mauve carpet when I was a student. The trees flower from September to November – the periods differ slightly in different parts of the country. Certainly it was an urban myth in my student days that if you had not started preparing for the end-of-year examinations by the time the Jacarandas blossomed, your chances of getting a good pass were diminished. On the other hand … if a blossom fell on your head, you were bound to be fortunate in one way or another! The flowering season starts later in the Eastern Cape and so that myth would hold no water for the Rhodes University students in Grahamstown, for example.

Jacaranda blossom

Why then would this beautiful tree fall foul of the alien audit of my garden? Some years ago the government listed the Jacaranda as an invasive species that required eradication – can you imagine the uproar that resulted in places such as Pretoria? This is because they tend to invade river banks, rocky ridges and gorges in some parts of the country such as Limpopo, KwaZulu-Natal, Gauteng and Mpumalanga. The classification is in line with a countrywide decision to get rid of invasive aliens (this includes some species of eucalyptus as well as black wattle) in order to improve the natural supply of water from rivers and other wetlands.

A compromise was reached: although Jacarandas are still regarded as invaders, existing ones do not have to be eradicated. No further trees may be planted though and so they are no longer available at nurseries. We have some Jacaranda trees growing on the verge and in all the years we have lived here I have not found a single seedling growing in my garden. I commented last month on the exquisite carpet of mauve flowers covering the pavements and streets in the early morning. The reprieve on total eradication is appreciated.


For years now, South African gardeners have been urged to rid their gardens of invasive alien plants. Ironically, many of these plants were recommended to us as ‘fast growers’ by the local nursery when we started our first garden from scratch in Pietermaritzburg many years ago. Times have changed, along with a broader understanding of how some of the more aggressively spreading alien plants can displace our indigenous vegetation. The former tend to grow well because they are not prey to local insects or diseases.

While we can look back with satisfaction at all the indigenous trees we have planted in our present garden over the years, and having got rid of an infestation of Lantana spp. – as attractive as they are – a recent ‘audit’ shows that we still have a way to go. Many of these plants were either inherited with the garden or have arrived uninvited. In this occasional series I will highlight some of the alien visitors we still need to see the back of.

The first is an old ornamental stand-by in gardens all over the country, the hardy Sword Fern (Nephrolepsis exaltata).

sword fern

Swathes of Sword Ferns have commonly been used to fill empty spaces where ‘nothing else will grow’ and have even been given pride of place in large pots to provide a flush of green on hot verandas. If you look around, many city buildings have Sword Ferns growing in neglected cracks and they feather damp patches in old walls and outbuildings. Sword Ferns have been popular because they are tough and apparently drought-resistant – qualities that have endeared them to even the most lacklustre gardeners.

sword fern

The Sword Fern is an import from North and Central America, however, and is difficult to get rid of once it takes hold of one’s garden. I can attest that the small patch we inherited has spread vigorously, almost taking over the area where the infestation began and in doing so has crowded out some of the plants that were growing there. Try pulling them out and you are met with stolons and tubers that break off and get left behind to spawn another colony while your back is turned! Apart from the afore-mentioned, Sword Ferns are also spread by the dispersal of their wind-borne spores.

sword fern