A tale of four swamps
I've made a project of keeping some level of control over the weeds in and adjacent to the parks and reserves near my home. This includes a seasonal swamp in the Len Howard Conservation Park. I've called the area the Big Seasonal Paperbark Swamp (BSPS), for lack of any formal name. The two most common, conspicuous and invasive weeds in the reserves discussed on this page are fleabane (several species of the genus Erigeron) and false onion weed (Trachyandra divaricata), otherwise known as strap weed or simply onion weed. Other weeds that I am working at removing from the BSPS include Centaurea melitensis, Maltese cockspur; Solanum linnaeanum, devil's apple and Solanum nigrum, Black nightshade.
Contact: David K. Clarke – © |
A part of the northern end of the BSPS reserve
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Most of the Big Paperbark Swamp Mob. There are at least 24 kangaroos in the photographed area. They all live in the vicinity of the reserve, although it's not uncommon to see them grazing nearby lawns.
This reserve has been badly infested by fleabane and false onion weed in the past. Photo iPhone 11 Pro, telephoto lens, 6mm, 2022/07/26 |
Introduction
People value, or at least should value, their public parks. I see many people whenever I'm walking, riding or working in one of them. I'm sure that many people get great enjoyment and relaxation from their parks. The fact that there seems to be very few who are willing to look after them has long been a mystery to me. All the parks and reserves I've written about on this page are in or near Mandurah, a city of 100,000 people about 70km south of Perth, the capital and largest city in the state of Western Australia. There are, of course, many people who put in voluntary time contributing to looking after the things and places that we love and value, but I do wonder why there are so few who are willing to work at controlling weeds in parks and other public places? It is likely that some people are reluctant to start because they are not sure which plants are weeds and which are natives. That is understandable, but a bit of time spent in study and identification would soon fix it.
Anyone who wanted to try would not necessarily take on a whole park, they could easily start in one section of one of the parks. Do as much as they wanted and a section at a time. Should anyone want help getting started, they could contact me; my email address is on the About Me page.
Tamworth Hill Swamp Reserve, Baldivis
Tamworth Hill Swamp Reserve was the first place in the Mandurah region where I came across fleabane that was thoroughly out of control (photo on the right, taken 2022/03/02). The fleabane is by no means throughout the reserve, but there are many places near the walking trail where it is in large numbers. It struck me at the time that it would be disastrous to the Len Howard Conservation Park, near my home in Erskine, if fleabane was to colonise it in a similar way. I saw plants around three metres tall in the Tamworth Hill Swamp Reserve. Apparently conditions there are ideal for the growth of the weed; conditions in parts of the Len Howard Reserve would be much the same.
I visited Tamworth Hill Swamp Reserve again in mid December 2023 and the situation had not improved. I saw many areas that fleabane had invaded, the second photo is just one such.
Marlee Reserve, Mandurah
Like all the parks I've covered on this page it is attractive and popular with walkers and joggers.
It is also home to one of the Mandurah giants.
Both fleabane and onion weed readily colonise bare or disturbed areas. Onion weed has become established near one of the other of the Mandurah giants. Fleabane plants can generally but pulled out, false onion weed needs to be dug out to get the bulbuls out of the ground.
Click on the image to see it in higher definition.
Black Swan Lake Reserve, Lakelands
The photo shows many tall fleabane plants as they were in winter, after they had gone to seed and dried.
As with any of the weeds, it would be quite possible to gradually eradicate them, one section of the park at a time.
Scotch thistles are also fairly common. (In Bowman Park, SA I have found spraying Scotch thistles with glyphosate the best way of controlling them, it is difficult to remove enough of the root by hoeing them out.)
Photo iPhone 11 Pro, standard lens, fl 4.25mm, 2024/01/09
An example of how to provide a perfect seedbed for the establishment of weeds
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Fleabane seeds move about with the wind. They would settle in placed like this cleared strip and find a perfect place to germinate without any competition.
The photo below shows the likely result that I'd expect a year or two later.
Photo iPhone 11 Pro, standard lens, fl 4.25mm, 2024/01/09
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Photo iPhone 11 Pro, standard lens, fl 4.25mm, 2024/01/09
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The outbreak in the photo on the right was far enough from the path to be easily passed by without seeing, it was among the trees in the northeast part of the BSPS.
This gives a hint of how bad fleabane could be in the LHCP if it was unchecked but as I'm pulling or digging out all those that I can find as soon as I find them fleabane (and onion weed) is becoming scarce in the BSPS.
In fact I seem to be making good progress on removing both of these major weeds from the area within a kilometre or two of my home (December 2023). I have pulled or dug out tens of thousands of plants of each of the two species.
There is a record of my work on fleabane and onion weed on another page.
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I believe that I have, with some help from Council, largely controlled this invasive weed in the BSPS reserve.
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The BSPS; a lovely public place, too beautiful to allow it to be taken over by weeds
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Erskine had a wet winter, at least up to the time of photographing this, 2022/07/24. By my records there had been 129mm of rain in May, 148mm in June and 109mm up to 24th of July. Consequently the Big Seasonal Paperbark Swamp was full and overflowing into the main estuary pool.
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Consequently few people see the full beauty of the swamp, as I do when I walk through it looking for weeds. One of the bonuses of looking after the park.
This section of the BSPS is flooded each winter.
End wordIf I, at the time of writing a 78 year-old, can control these two invasive species in the BSPS (and in other public places near my home) surely there are a few others who could do the same in the other reserves, and in parks and reserves everywhere.We can all, and should all, contribute to looking after our shared public areas. A motto I use is: If I see something that needs fixing and I'm capable of fixing it and I don't fix it, why should anyone else? |
References and related pagesOn this site...Looking after what is goodEthicsClimate change; a threat far greater than invasive weeds in local swamps Environment; it's what we all share and we should all help look after it Do something, don't just walk by We can and should all make a contribution to the good things in our local area Picking up rubbish in public places In the Mandurah areaControlling fleabane and other weeds, MandurahPeel Estuary and Mandurah - Observations Mandurah volunteers, a page to try to connect them Bicycling in Mandurah; some comments on enjoyable places to go on your bike. Further afield in WAImages of WA, from a visitor |
IndexOn this page...The Big Seasonal Paperbark Swamp (BSPS), MandurahBlack Swan Lake Reserve, Lakelands How to provide a seedbed for weeds This one in Black Swan Lake Reserve, Lakelands End word Marlee Reserve, Mandurah References and related pages Tamworth Hill Swamp Reserve Two differences between the reserves |
