The pavement specials

People look at these and say "Ooh pretty" but they are a serious problem plant and an invasive species that pops up everywhere. Madagascar periwinkle, or Catharanthus roseus is also a popular medicinal plant which contains anticancer compounds and used for anything and everything from diabetes to insect stings. There are some serious safety concerns with this plant though because it contains toxic compounds called alkaloids. Vinca alkaloids are the source of a various chemotherapy drugs such as Vincristine but would I use it at home? Not likely.

Madagascar was once part of Africa so it shares the same geology and many plants from Madagascar become highly invasive in Africa because soil and weather conditions are very similar but the normal pests that keep these plants in check don't exist here and they invade damper places and outcompete the natural vegetation, destroying the more fragile biodiversity.

I have read that invasive species can actually be a good thing because they can recolonise disturbed places but in practise, that doesn't seem to be the case. Periwinkles are also so tough that they are popping up from cracks in the pavement so they are a real nuisance and truly invasive plants like this can colonise almost any environment. Their Afrikaans name is "Begraafplaasblom" meaning "cemetery flower" so they are flowers that could be planted on graves and neglected. This is another case of a pretty garden plant that doesn't stay in the garden and I need to do a late-night removal of these, when the neighbours won't see me to complain.