Alien Invader Plants Project
Pink Alert: Pompom Weed
Spring and Summer are the seasons
when many of the alien weeds and invader plants resident in South Africa begin
to display their gaudy wares. The flowers of many of these species has given
rise to the familiar “beautiful but dangerous” catchphrase that has become
synonymous with invasive alien plants.
One of the more
distinctive and, unfortunately, ever increasing displays is that of pompom weed
(Campuloclinium macrocephalum).
Pompoms are the
distinctive hand-held ornamental tufts that have been made famous by American
cheerleaders. They bring connotations of applause, goodwill, possibly even
excitement. Unfortunately, their namesake in the world of alien weeds and
invasive plants provide starkly contrasting emotions for weed scientists, nature
lovers and landowners.
Pompom weed is an
invasive weed of grasslands that threatens conservation and agriculture in South
Africa. A member of the daisy family (Asteraceae), this South American
overstayer is rapidly displacing native species, reducing both the biological
diversity and carrying capacity of vleis and veld. Infestations become
conspicuous when the plants are in flower, usually between December and March,
transforming the landscape from green to pink. The plant initially
establishes itself in disturbed sites, such as roadsides, but then invades
grasslands, open savanna and wetlands.
Currently, this
weed is most prominent in Gauteng, but is expanding its distribution into
Limpopo, Mpumalanga, NW Province, KwaZulu-Natal, Eastern Cape and the Free
State.
Modeling
exercises indicate that the potential distribution for pompom weed includes the
majority of the eastern half of the country with only the Western Cape and
Northern Cape expected to escape the pink plague. Anecdotal evidence from
farmers, conservation officers, ecologists and WESSA members strongly suggest
that this weed has already begun to fulfill its potential. So what can we
do? If you see pompom weed please record the date and location of where
you saw it. Contact the Alien Invader Plants Project (031 201 3126 or
edenjw@mweb.co.za) so that your sighting
can be verified and recorded. Depending on the extent and density of the
infestation we can proffer advice on the best techniques for management and
alert the relevant authorities.
Eden Wildy
Alien Invader Plants Project
As I am sure u have all noticed,
Pompom Weed Campuloclinium macrocephalum continues its spectacular "big
bang" population increase on the M13 and N2 between Paradise Valley and
Westville near Durban. There are also pockets of invasion in the Outer West
area of Durban and
Wally Menne of the Botanical Society of South Africa (BOTSOC) says also on the Natal South Coast.
He adds that the 'Pink Peril' is far more widespread than people realise.
"I recently saw a patch next to the freeway on the inland side of Howick, and
quite a lot of scattered
individuals in Mpumalanga Province". Invasion biology tells us that
prevention is better than cure. This weed has the potential to be a transformer
species in natural grasslands. Braam Van Wyk, a well known South African
botanist and a Professor of Botany at the University of Pretoria, sees it as a particular menace.
How long before it is in Paradise Valley, New Germany commonage, Palmiet Nature
Reserve and Krantzkloof Nature Reserve? Have you seen it in Johannesburg? Impressive!
To be a little controversial, whilst we are all good at preaching the anti-weed
doctrines I think we can be a lot more effective in where we place our
resources. This plant and the new invasion is a case in point. Can't we put
our collective minds together to nail this one starting in the eThekwini
Municipal Area.
Richard Boon
Contract Consultant, Environment Branch
Development & Planning, Durban Metro
P.O. Box 680, Durban, 4000
Jeremy Goodall of the Plant Protection Research Institute (PPRI), Cedara has been undertaking herbicide trials for
pompom weed. Along with Lesley Henderson of PPRI of the Agricultural Research
Council of the Department of Agriculture, and author of the popular book "Alien
Weeds and Invasive Plants"
and Hildegard Klein alos of the PPRI, he has produced a
2-sided A4 fact sheet on pompom pertinent points contained within the fact
sheet:
"Pompom weed is sensitive to a range of
herbicides but as yet no herbicide has been registered for its control.
Physical methods of control include
uprooting and burning the plant. However this is only recommended where there
are few plants as disturbance of the soil will only encourage further invasion
of weeds.
Spread of the plant can be limited by
preventing seed production. Aerial stems can be cut right back before the
flowers produce seeds. However be warned that the plants will be stimulated to
produce more stems and in order for this method to work the plants will have to
be cut back several times until the end of the growing season. Repeated cutting
back of aerial growth should deplete nutrients stored in the roots, weaken the
plant and limit seed production. This method however is only practical on a
small scale."
The sheet is dated July 2003. Jeremy can be contacted at
ntjg@natal1.agric.za
Eden Wildy
Alien Invader Plants Project
Wildlife & Environment Society of SA
100 Brand Road, Durban 4001
PLEASE HELP!
Lesley Henderson from the Plant Protection
Research Institute (PPRI) would like to receive locality records of pompom weed
for the Southern African Plant Invaders Atlas (SAPIA) database.
Anyone seeing pom-pom weed in new areas, please email Lesley at
lh@nbipre.nbi.ac.za
This page was last edited on
22 April, 2006
