Each Plant produces thousands of seeds which change from green to black when ripe and are each marked with a white spot.

Alien Plants
Printer Friendly Version

Extract from the Wildlife and Environment Society of SA (WESSA KZN NEWS)

As usual at this time of the year particularly in Coastal KwaZulu-Natal, Mother Nature is at her bountiful best. Neat tidy little winter gardens suddenly resemble jungle patches and Madam is rather sorry that she had fallen for all those plants that were on sale at the local Nursery the previous year. Surprisingly many of her purchases have just run wild and are seeding themselves everywhere or are aggressively swamping everything else in her garden. She tells 'John' that he must trim here and prune there and remove all this rubbish. When John asks what he should do with the mountain of Pereskia fronds, seed-laden branches of Camphor trees, Yellow Bells, piles of Mexican Sunflower heads, the accumulated heads of Wild Canna, Wedilia Tickseed, Sword fern, Chandelier Plant and many many more, Madam is faced with a dilemma! There is no room in her tidy garden for all this unwanted plant material. What should she do?

Then Madam, in her ignorance sets in motion an inexorable chain reaction that is set to cost the country millions for the subsequent eradication and control of these garden escapees. She instructs John to take his barrow-loads of alien infested rubbish and to dump them on the vacant plot just down the road. Other gardeners in the area follow suit and soon there are 50 or 60 or more declared invaders let loose in the area.
Compounding the problem is the fact that a stream wanders through the vacant lot just below the bank where the excess garden rubbish has been dumped. Downstream of the plot are a number of vitally important natural habitats including a pristine grasslands area, a beautiful wetland, home to a number of threatened frog and insect species, and a nature reserve that the local conservationists have spent hundreds of man-hours and thousands of Rand restoring to near perfection. All are now under direct threat of invasion from the dump site. Adding to the time bomb effect is the fact that the prevailing wind blows from the plot towards the nature reserve and grasslands. Madam, and thousands like her, blissfully unaware of the consequences of her actions, solves her immediate gardening problem and creates a monster whose powers of destruction, particularly in our climate, are phenomenal.

This common scenario is only a small part of the problem but is one that we need to be very aware of if we are to maintain progress in our fight against the destructive effects of introduced alien species. Our goals should be not only the prevention of the spread of old weeds, but the proactive detection and prevention of new weed problems. Each and every one of us must be aware of the potential for introduced plants to become garden escapees and tomorrow's nightmare alien invaders. We must continually be on the alert for any new plants that are suddenly 'popping up' in our gardens or in disturbed areas because prevention is always better than cure.
Jean Moore

Chromolaena odorata: (left) Public enemy No. 1 Also known as Triffid. Believed to have arrived in Durban with packing material during the Second World War. This Category 1 invader from Central and South America is already costing South Africa millions of rands in lost grazing and eradication. Each plant can easily disperse millions of seeds which are carried by wind, water and birds. If left unchecked it will scramble up the tallest trees eventually smothering and killing them. Uproots easily but beware... in damp conditions it will send roots down from the stem where it lies on the ground. An alien nightmare!

If you see them kill them!

Lantana camara: Rated as one of the ten worst weeds in the world. Compact bushy shrub or untidy scrambler. Will smother trees up to ten meters tall. Has square stems with rows of small thorns. Flowers pink and orange are followed by fruits which become purple black when ripe. Birds rodents and monkeys help spread the seed. Lantana is poisonous to humans and domestic animals. Lantana and all its hybrid forms are proclaimed noxious weeds throughout South Africa. Not to be confused with indigenous harmless Lantana rugosa (Birds Brandy) which is much smaller and has light purple edible fruit.

Bugweed: Solanum mauritianum. Originally from South America this plant can grow to the size of a small tree. Even young plants produce clusters of fruit which are soft and yellow when ripe. Poisonous to humans but extremely attractive with birds who unwittingly propagate this alien invader. Bugweed has large oval leaves and purple flowers at the end of the branches. Like most aliens it grows very fast. Care must be taken when clearing these plants as they dislodge fine hairs which contain toxins that may cause allergic and breathing problems in workers.

 

Syringa: Melia azedarach. Originally from Asia this attractive, deciduous tree is rapidly invading large areas of the Palmiet Reserve.In spring the tree is hung with clusters of fragrant, pretty, pale mauve flowers. These are followed by drooping clusters of brownish-yellow berry's that become wrinkled when ripe. Individual parts of the tree have varying toxicity. There are many reports of death after eating fruits or other parts of this tree. Birds especially Purple Crested Turacos (Formally Loeries) use the fruit and spread the seeds.

It appears Syringa's might have some medicinal properties and research into this is ongoing

To Kill... Debark and follow up with suitable herbiside

 

Balloon Vine Photo  Clive Read 2003

Curtain of Death... A Balloon Vine (Cardiospermum grandiflorum) above strangles the locals in the Palmiet Nature Reserve while a Ginger Lily (Hedychium coronariusm) below prepares to propagate more seeds. South Africa's indigenous wild Ginger is now extinct in the wild mainly through muti collection. Herbariums are attempting to preserve the species in indigenous plant nurseries..

 Ginger Lily . Hedychium coronariusm Pretty but an Alien  Category 1 Photo Clive Read Palmiet Feb 2003

Chromolaena odorata Public enemy No. 1 Photo Clive Read March  2003
Lantana camara /Tickberry Category 1

 

Syringa's spread rapidly especially along theriver banks of the Palmiet. Photo Clive Read March 2003
Palmiet Nature Reserve12 Jan 2005
Copyright © 2007 All Rights Reserved