(Extract from Spotter Network Newsletter - for more information www.capetowninvasives.org.za)
When are pompoms not a good thing?
In May of last year (2013) a report came in to EDRR of suspected Pompom weed growing in the Company Gardens in Cape Town.
Pompom weed (Campuloclinium macrocephalum - follow the link for more information) is a major weed of grasslands in Kwazulu-Natal and further north in the country and has never before been reported in Cape Town. The population of Pompom was removed immediately, however, at that time most of the mature plants had already set seed.
The manager for the Gardens indicated that these plants have been growing in this single, hot rockery for at least 7 years without spreading, the origin of which is unknown. Perhaps this species, despite clearly being naturalized and able to set seed, is still in its lag phase before serious colonization takes place.
A follow up visit took place now in January 2014. We counted 80 plants of which 31 plants were in full flower or about to flower. A survey revealed that no other populations were to be found at any other location in the gardens. Over 100 flowering heads were collected for incineration and the plants were dug out by their roots or sprayed with herbicide where they could not be dug out. The next follow-up visit is scheduled prior to the next flowering season.
This is one reason why it is so important to identify emerging weeds and target these while populations are still localised and population levels are not beyond that which can be contained and possibly eradicated. Once populations are widely established, costly operations are required to contain and/or control such populations to mitigate negative impacts. The costs associated with EDRR efforts are less than those of long-term invasive species management programmes.
This is a great example of the possibilities of successful partnerships and also shows the importance of every spotter record and sighting sent to us.
This month we focussed on Spanish Broom before all the seed is released and Red Valerian as they are still in flower. We have tackled some large sites such as UCT and Groote Schuur, clearing these two species as well as some Pampas Grass. In Brackenfell, next to Bracken Nature Reserve we cleared a large stand of Spanish broom that had started to encroach into the Nature Reserve. We have also cleared several Spanish Broom sites in Phillipi. Hout Bay has also kept us busy with lots of Red valerian still in flower. We have been mainly busy on Klein Leeukoppie, where the Red Valerian has covered large expanses of the koppie. Chart Farm has kept another team busy for the entire month, clearing Spanish Broom, Red Valerian and quite a few Australian cheesewoods. We also did a follow up of Tree of Heaven on Groot Constantia.