Grocott's Mail

Toxic invader from Brazil is aggressive

Inkberry

( Cestrumlae­vigatum) (Category 1b throughout South Africa, meaning it requires compulsory removal or control by all landowners and Organs of State).

What does it look like?

Usually a multi-stemmed shrub to medium-sized tree, but can also become a large tree (up to 15 m). The leaves are fresh green, and have a characteri­stically unpleasant odour when crushed. The small, tubular flowers come in sprays in the axils of the brachlets. The fruits are small, black ovals full of (poisonous) black juice (and from where name ‘inkberry’ comes from). The wood is soft and pale, and very brittle.

Where does it come from?

Brazil.

Why is it bad?

A highly aggressive species that outcompete­s indigenous vegetation, especially in moister environmen­ts such as in riparian zones and in coastal bush.

It is very common in gardens (both urban and farm gardens) in the Grahamstow­n area and along the Sunshine Coast (such as in dune scrub and forest in Port Alfred).

Birds are the main culprits for spreading it, but it also increases locally through suckering.

The whole plant is toxic, both to people and livestock. It is also highly invasive in KwaZulu-Natal, Mpumalanga, Limpopo and along the Orange and Vaal Rivers.

There is surprising­ly little informatio­n on where it might be invasive elsewhere in the world, except for other parts of southern, western and eastern Africa and St Helena Island, with a related species C. parqui (Green Cestrum, also Category 1b in South Africa) a problem in Australia.

How can I control it?

Larger trees can be felled; the wood is quite soft, and removing these trees is quite easy, even with an axe or panga.

It is essential that the bark of the stumps be stripped to ground level and the whole stump painted with a suitable herbicide to prevent coppicing or resproutin­g.

Younger plants can be treepopped/hand-pulled (provided they are not suckers), or cut near the base and treated with a suitable herbicide (if suckers).

Mass small plants (>2m) on farmland can be sprayed with a registered herbicide.

How can I replace it?

There is a multitude of indigenous replacemen­t options for this species. In coastal areas consider the ornamental Dune Soap-berry ( Deinbollia oblongifol­ia) or the dense Camphor Bush ( Tarchonant­hus camphoratu­s).

For more inland areas consider Dogwood ( Rhamnus prinoides). The fast-growing Cheesewood ( Pittosporu­m viridiflor­um) would be a good option to recreate the clusters of yellow flowers effect (somewhat). To replace larger specimens, consider Natal Mahogany ( Trichilia dregeana), Cape Beech ( Rapanea melanophlo­eos).

For replacing Inkberry hedging and screening, consider Bladder-nut ( Diospyros whyteana) and Kooboo-berry ( Cassine aethiopica). Along rivers, Safsaf Willow ( Salix mucronata) would be an excellent replacemen­t.

•For alien invasive species advice, property assessment­s, alien control plans and practical implementa­tion of control actions, contact The Alien SWAT Team: Dr Ralph Clark 072 439 8981, Mr Timothy Mattison 060 527 7816; thealiensw­atteam@gmail.com.