Article 86 Psidium guajava - Botanical Society of South Africa

Weeds in our Area (Part Eighty Six)
By Bob and Ena McIntyre – Garden Route Branch
The common Guava, Psidium guajava,
Many of us would be taken aback if this popular dessert fruit could no longer grace the dining
table in all its many guises. The Psidium guajava, (Common Guava) has an invasive status of
transformer and is classified as a category 2 declared invader (allowed only under controlled
conditions). Native to South America, the Guava was introduced into South Africa as an
agricultural crop. Like so many other useful plant species because of its commercial value, it too
has escaped from the orchards and established itself in the wild becoming a serious invasive weed,
mainly in the eastern areas of our country, particularly in KZN and Mpumalanga low-veld.
Indications are that it is spreading westwards along the coast into the Eastern Cape and signs of
wild plants are appearing in our area. The negative impacts of the uncontrolled infestations of the
plant are twofold. The growth habits crowd out indigenous vegetation transforming the landscape
and wild unattended plants act as hosts for fruit flies which in turn impact on the commercial fruit
production of other fruits. Those of us with plants in our gardens for home consumption should
bear in mind that the fruit is also enjoyed by birds, baboons and monkeys and to prevent the
spread of Guava seed by our feathered and furry friends we need to take some precautions. The
most practical method will be to protect fruit for your own use and to remove any excess fruit
from your tree before the seeds become viable. This small thoughtful action on our part will
contribute to protecting our natural environment while we continue to enjoy the nourishing
goodness of Guavas.
Identification: The Guava is a perennial evergreen
shrub or small tree. The leaves are stiff and quite
thick, green-bronze in colour, oblong-elliptic,
broad and rounded at both ends with
conspicuous veins. The flowers are small, white in
colour and in groups of one to three. The plant
invades forest margins, roadsides and watercourses. Once established the Guava is not easy
to eradicate. It has a strong root system, coppices
when cut and produces vigorous root suckers.
Ring-barking, strip-barking and felling encourages
root suckering.
Control: Many unregistered herbicides are
ineffective because of the robust root system.
Other than the complete removal of all roots the correct use of a registered herbicide is the only
solution. Chopper and Hatchet are registered for cut stump treatment and will also work with a
frill. For foliar application Plenum 160 ME is registered. Please remember that the correct,
responsible and careful use of herbicides is essential to avoid negative impacts on the
environment and any indigenous vegetation.
References: “ALIEN WEEDS AND INVASIVE PLANTS”: Lesley Henderson. Copyright © 2001
Agricultural Research Council,