A suffocating carpet
Smooth and Striped Wandering Jews ( Tradescantia fluminensis and T zebrina) (Both are Category 1b in South Africa – they must be controlled by the property owner, and may not be cultivated or sold).
What do they look like?
Both are creeping ground covers. Smooth wandering Jew has green leaves and white flowers, while striped wandering Jew has striped grey-green and silver-white leaves, with pink flowers. Both are very common ground covers in local gardens. Without flowers, smooth wandering Jew could possibly be mistaken for our indigenous commelina species, but none of our indigenous species form extensive carpets like smooth wandering Jew and they have blue or yellow flowers. Tradescantia pallida (purple wandering Jew) has also been flagged as a potential problem plant, but it is not listed at present, and does not seem to be a problem in Grahamstown.
Where do they come from?
Brazil (smooth wandering Jew); central and northern South America (striped wandering Jew).
Why are they bad?
Both wandering Jews have naturalised into our indigenous forests, woodlands and watercourses within and around Grahamstown. They form dense carpets in deep shade and suppress the regeneration of forest and woodland trees and smother low-growing indigenous vegetation. Carpets of wandering Jew can become a foot deep, completely out-competing under story bulbs such paintbrushes ( Scadoxus and Haemanthus) and clivia. They clog seasonal watercourses, and get washed downstream to form new colonies when these watercourses experience high flows. Fragments are also distributed by Photo supplied animals, people and even wind. Elimination of the leaflitter habitat in our indigenous forests by wandering Jews compromises the ability of those forests to support forest floor bird and animal species. Striped wandering Jew contains a sap which is a skin irritant if handled extensively. Wandering Jews are recorded as problems in Gauteng, KwaZulu-Natal, parts of the Western Cape, and locally also in Port Alfred and Bathurst. Further afield they are a menace in parts of Asia, Australia, New Zealand, the south-eastern US and some oceanic islands.
How can I control them?
Small infestations of these plants are relatively easy to control by manual removal, but require repeated followups, as every piece left will grow into a new colony. Foliar application of a suitable herbicide is possible for very extensive stands which would otherwise be labour intensive to eradicate. The challenge with herbicide use for smooth wandering Jew is that the waxy leaf-coat impedes absorption of the herbicide, and a penetrant is advisable for large infestations. Sheep are partial to smooth wandering Jew, and can be used as a biocontrol agent on farms.
What can I replace them with?
In gardens they can be replaced with numerous shadetolerant indigenous ground covers such as fairy Crassula ( Crassula multicava), lobster flower ( Plectranthus neochilus), thicket spur-flower ( P madagascariensis), speckled spur-flower ( P ciliatus), creeping foxglove ( Asystasia gangetica) and hypoestes species. If you have indigenous woodland or forest on your property, ground cover replacement is unnecessary: healthy deep-shaded forest is usually free of ground cover and is preferred as such by many ground-foraging birds such as lemon dove, chorister robin, spotted thrush and buff-spotted flufftail.
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, Timothy
Mattison 060 527 7816; thealienswatteam@gmail.com.