ACACIA LONGIFOLIA

They look attractive both from afar and from close-up. These evergreen trees have long bright green, spear-shaped leaves and are covered with bright, finger-shaped, yellow flowering heads during the winter.

The Acacia longifolia (Long-leafed Wattle) is one of several species of wattle brought to this country from Australia well over a century ago to assist with the stabilisation of sand dunes near Cape Town. They have since spread to other parts of the country, being particularly invasive in both the Eastern and the Western Cape, Kwa-Zulu Natal and in parts of Mpumalanga. Such is the nature of introducing an alien species from one country to another, only to find that it not only flourishes to the detriment of indigenous vegetation but appears to have no natural predators in its new abode.

In some areas Acacia longifolia has also been planted as an ornamental shrub. Looking at the flowers, it is easy to see why.

These trees form dense, impenetrable thickets that threaten the existence of indigenous vegetation. Given that South Africa is a water-scarce country, it is concerning that the Acacia longifolia trees have spread so widely, both on hill slopes and along the country’s riparian zones. Seedlings grow very quickly – several others are visible behind the one in this photograph.

One of the methods employed to curb the rampant growth of the Acacia longifolia has been to release biological control agents, such as Trichilogaster acaciaelongifoliae, an Australian bud-galling wasp from the Chalcidoidea family that parasitizes these plants. This wasp species was introduced in 1982. They lay their eggs in the immature flower buds. Chemicals secreted by the young grubs induce bud galling. The larvae live and feed on the plant tissue inside these galls, which helps to reduce the reproductive potential of the wattle.

The Working for Water Project has made inroads by physically cutting down stands of wattle and applying herbicide to the stumps. Landowners, however, do not always seem to follow up on this initial clearing process and we can see the proliferation of these trees along the country roads we often drive along in this area.

I cannot help wondering about the future of this former grassland for these cattle to graze on.

WINTER SKELETON

Did the title grab your attention? I assure you that no cupboards have been opened, nor was this written on a ghoulish windy night with the moon scudding behind dark clouds accompanied by the screech of owls and pinging of bats in my ears.

Instead, this is a Datura plant – seen here in its spring glory.

This is a different plant at the end of the winter.

The dry stalk is akin to the skeleton of the plant, now stripped of leaves and any life-giving sap that once ran through it. The seed pods too have dried up and shrivelled into spiky shells of their former fruitfulness.

Dry winter winds have long since shaken the pods and dispersed the seeds to grow new plants in disturbed soil wherever they have landed. There is nothing left.

In time the frail skeletal remains of this plant will fall over and gradually become one with the soil that nurtured its beginning.

THE ALIEN MORNING GLORY

I photographed these very pretty Morning Glory flowers growing along the fence bordering the Botanical Garden six years ago. I particularly enjoyed the mix of blue and purple and seriously wondered if I should collect seeds to plant in my garden. There is no denying that these flowers are eye-catching. I was not alone thinking so, for during the 1950s plants such as these were actually promoted for covering walls and fences – particularly as it can also grow well in poor soil.

Alas, I found out that they are regarded as unwelcome alien invasive plants here in the Eastern Cape as well as in other parts of the country. Scientifically known as Ipomoea indica, this pretty creeper hails from the West Indies and is problematic because it tends to smother other vegetation. It spreads by seed and does not appear to have any natural predators – thus continuing its creeping, suffocating march through areas where the growing conditions are favourable. These plants are quick to invade riverbanks, woodland, and wasteland areas.

Local gardeners need not go without though for there are a number of indigenous morning glories to choose from. Among them is the Ipomoea cairica, or Coast Morning Glory.

Picture: [pza.sanbi.org]

It is indigenous throughout tropical Africa, as well as in the eastern Mediterranean and occurs naturally in the Eastern Cape. This plant was first collected in Cairo, hence the species name cairica.

Another which is endemic to southern Africa, is the Ipomoea oenotheroides, also known as the Christmas Flower. A positive aspect of this plant is that it grows well in the arid parts of the summer-rainfall region.

Picture: [pza.sanbi.org]

FOCUS ON RED

It is an icy, grey day during which winter is stamping its feet in a determined fashion to freeze out any idea of spring unfurling in the wings. What better way of beating the winter blues than focusing on red:

Aloe

Greater Double-collared Sunbird

Amethyst Sunbird at nectar feeder

Gazania

Crassula perfoliata

Virginia creeper