Friends of Brixton St Brixton St Wetlands, Kenwick
Down on the flats at Brixton St hand removal of entire Watsonia bulbilifera plants (corms and all) combined with careful chemical control by the friends of Brixton St and ATCV volunteers over the last five years has been very successful example of weed removal resulting in the regeneration of the native vegetation. The Watsonia occurs on winter wet clay flats in Marri woodlands and Viminaria shrublands.Workers have been slowly moving from the areas of relatively good bush out to the denser infestations, carefully removing the whole plant when the soil is still soft from rain but not so wet that trampling and compaction are a problem. Larger plants have been wiped with 1:10 glyphosate from September through November. Species moving into the space left by the Watsonia include Mesomelaena tetragona, Tetraria octandra and Viminaria juncea. No other serious weedy species have become established where the Watsonia has been taken out. It will be some time before Watsonia is eradicated from the site and every year all flowering spikes are removed from the population to control spread. In September 1999 a monitoring transect was placed across the population to gain a more detailed understanding of the success of the control programme and of the species that are replacing the Watsonia
Friends of Shenton Bushland, Shenton Bushland, Nedlands
Across at Shenton Bush land on the Spearwood dunes Susan Worley and the friends of Shenton Bushland have been working on a project aimed at removing all Watsonia meriana with minimum impact on the surrounding Jarrah /Banksia woodland. The project started off in a small way in 1996 and in 1997 most of the large plants in the population were treated with glyphosate 1:10 applied with a squeeze bottle and sponge. In the summer of 97/98 a fire took out a large section of the bushland including the area Watsonia occurred in. The Watsonia plants that grew back the following spring were much smaller (younger?) than those of the previous year and it was unclear whether this was due to the 1997 spray program or the fire. There was much regeneration of native seedlings after the fire, however there was also a germination en masse of Gladiolus seeds. So the friends were left with small Watsonia coming up through the post fire regeneration of the native plants and a sea of germinating Gladiolus. The strategy for 1998 was to remove by hand the outlying plants moving in towards the denser areas of the population and at the same time control the spread of both Watsonia and Gladiolus by removing all flowering spikes. In September 1999 a monitoring transect was placed across the population. As we were fortunate enough to have a Green Corp team of 10 workers available for 2 days the entire population was wiped with 1:10 glyphosate.
Hovea Bush Regenerators Falls Park, Shire of Mundaring
An example of successful bush regeneration comes from the work of Jenny Johnson and the Hovea Bush Regenerators in the Jarrah forest at Falls Park in the shire of Mundaring. The area had been invaded by a very dense population of Watsonia for at least the last 30 years. The group sprayed the population for two successive years (1993/94) with glyphostate, as little native vegetation was evident. In the third year a late spring control burn was put through the area resulting in very successful regeneration of native species. What was interesting was that the presence of the Watsonia corms in the soil did not seem to prevent germination and establishment of native seedlings following the fire. (People often raise concerns about the physical presence of the corms preventing regeneration of natural vegetation). In fact removal of the corms in these areas (steep slopes and heavy soils) can result in serious erosion problems.
Follow up weed control was required after the burn, a particularly important aspect of such a strategy. Without follow up weeding after the fire the previous two years work could have been lost.