How to kill a cactus

In an earlier post, my mom asked for help identifying a cactus she has in her garden.  Ross came to the rescue, pointing out that it is a Cereus peruviana and a category 1 invader!  Needless to say, she now wants it out of her garden but if we cut it down with a panga we’re worried we’ll spread it around the garden and make the matter worse.

We also don’t want to use anything too toxic that would damage the environment and could get into the water table.  I’ve heard that you could use diesel but I’m not sure of the application and what the implications would be.  Any suggestions would be appreciated?

aliens garden


Syringas are my most hated of alien, invasive plants in Durban. They spread like wildfire, grow easily in this climate and are a task to remove. Since coming back to Durban last October I have seen more and more of them, and it seems that many people (myself included) don’t know the details.

A few Google searches revealed that what we erroneously call ‘Syringa’ is in fact Melia azedarach, the ‘Chinaberry’ Tree, which is part of the mahogany family and native to India, southern China and Australia. While some of the facts about the tree sounded familiar; the use of its leaves for medicinal purposes (also in Indian and Zulu communities in KZN) and the fact that its berries are toxic to humans but not to birds (which facilitates the spreading of the plant), I was surprised to find that it is commonly used as timber.

Melia azedarach has a timber of high quality, but is generally underutilised. Apparently, the seasoning of the wood is also relatively simple as it dries without cracking or warping and is resistant to fungal infection. I quickly did the Math. Durban is overrun by these alien and invasive trees that grow to around 12m, which equals a lot of crack-free, water and fungus resistant timber, that could be used as building materials or to make furniture etc. as in the case of Koop.


Indigenous Lantana

I remember as a kid getting lectured at school about the evils of lantana – I think I even went on a school trip to clear it out of our neighbourhood. Back then it was the number one invader species in Durban and everyone was out to get it (see more about invader species and, in particular, the Syringa berry in an upcoming guest post by Grant).

Imagine my surprise when a few years back I saw lantana for sale at my local, indigenous nursery.  Well, it turns out there is an indigenous species of lantana, with exactly the same flower and leaf structure as the invader.  The main differences are that this one is low-growing ground-cover as opposed to a shrub and the flowers are yellow as opposed to purple.  Plus, it is a great plant to have in your garden.  It flowers throughout the summer and the butterflies really dig it.

Lantana in bloom.
Lantana in bloom.