Oxalis pes-caprae

　

Found in range of locations from gardens to roadsides, the noxious weed Oxalis pes-caprae or soursob is a concern primarily in pastures and amongst indigenous vegetation. It is distinguished by three heart-shaped leaflets with or without stalks that fold in dull days or at night. Flowers are bright yellow in colour and open in sunlight and close at night. There are masses of underground bulbs which are spread by water, birds, in dumped garden waste and during cultivation (not to be confused with native varieties of oxalis which have no bulbs).

Although primarily a weed affecting cultivated areas, soursob in pastures has the potential to replace almost all desirable plants from the time of autumn rains to well into the spring reducing carrying capacity. Stock will selectively graze more palatable species than the soursob with its high oxalate content. Soursob has severe impacts on indigenous ground-flora with dense infestations eradicating smaller plants.

In terms of its control, soursob would have to one of the most, (if not the most!) difficult weeds to eradicate. Control is made problematic for two main reasons; firstly it is the vigorous network of underground bulbs that render hand weeding or mechanical removal ineffective. Secondly it is the irritating life cycle of the plant that limits effective herbicide use to a one week window at the bulb exhaustion stage. A one week window that could open at any time between May and July. Suffice to say soursob is a weed that takes several years to control. Another suggested method of control involves using a combination of light exclusion and raking however this would be suited to a garden situation. Cultivation and grazing are generally ineffective means of control.

The optimum time for herbicide control may have come and gone for 2010 but the weed is no more apparent than now. Take the time to check your priority areas of land. Soursob is one to keep in the back of your mind, as spring and summer pass you'll be well prepared to strike with vengeance come autumn next year. Information on how to determine the bulb exhaustion stage will be provided as part of weed talk next year (prior to the optimum control time). If you would like further information on soursob please contact Kate Williams, Project Officer with the South Gippsland Landcare on (03) 5613 5973 or email katew@wgcma.vic.gov.au

Aside from wattles, cape ivy would have to be the most distinctive plant at this time of the year in Gippsland, coating the landscape with patches of bright yellow. A perennial plant that grows as a ground cover or climber (given the opportunity), cape ivy is a problem plant to both native bush lands and household gardens. It forms a thick mat that smothers all vegetation within its 10m high reach.
Cape ivy, as with English ivy will only flower and produce seed on parts of the plant that become vertical i.e. climb up trees. Therefore when controlling, start with the vines growing up the tree to prevent flowering and further spread by seed. Cut climbing stems with secateurs and leave to die in shrubs or tree. Immediately paint with a suitable herbicide any cut stump that is to be left in the soil. For larger infestations spray foliage with herbicide, taking care to avoid spraying any native vegetation that the plant is climbing through. If using herbicide, paint/spray when the plant is actively growing from June to September. If controlling cape ivy in a garden situation, consider replacing it with a suitable plant such as native Clematis. There are a number of different types of Clematis plants to choose from, each suited to a range of conditions. 
When controlling unwanted plants, whether it’s in your local patch of bush or burkes backyard next door, it’s important to have the end result in mind. Having a mental picture of what you want to achieve will steer you in the right direction and make the end result all the more satisfying!

Buyer Beware of  Bluebell Creeper!
Bluebell creeper; an evergreen climber, producing attractive flowers, tolerant to a rage of growing conditions and native to Australia. With all this in mind it comes as no surprise that bluebell creeper can be an avid gardener’s plant of choice! Native to Western Australia’s south coast, the creeper is undoubtedly well suited to Victoria’s coastal areas. From a gardeners point of view this is ideal, from the perspective of Victorias natural environment however, not so ideal. As with many plants for sale at the local nursery, all bought with good intents and purposes, bluebell creeper has found its way beyond the back yard fence into natural areas. The plant doesn’t get to these areas trough creeping, (as the name suggests) but rather it is spread far and wide by birds and foxes. Ripe seed is carried during the months of March to May and wherever the fox or the bird goes, so too a new plant will emerge! Beginning as isolated plants, bridal creeper fast develops into an aggressive invading front that smoothers all vegetation in its path. Such is being evidenced in coastal parts of South Gippsland.
 The control of Bluebell creeper has recently been assessed as a high priority for Parks Victoria in coastal areas of South Gippsland. The assessment rated weeds according to the threat or impacts posed by a particular species i.e. effect on native flora. Results of the assessment determined that if left uncontrolled bluebell creeper has the potential to significantly degrade coastal vegetation communities.
Local Parks Victoria Ranger David Farrah explains “controlling bluebell creeper infestations in areas such as Cape Liptrap Coastal Park is a must, without adequate control the quality of native vegetation within this coastal zone is compromised”.  For those with bridal creeper, it’s not to say that you should drop everything upon reading this and immediately remove all traces of the plant from your yard. Rather the idea of this article is to raise awareness about the threats associated with the plant. Be conscious of the land use in surrounding areas- no garden is an island. If your property is close to areas of native vegetation vulnerable to invasion be mindful that it can spread. Consider phasing out the creeper by replacing it with a suitable alternative. Control is best achieved in August to late September whilst the plant is actively growing and before the plants flower and bear fruit.
 When selecting plants for your garden as a general rule ask yourself two basic questions 
1) how it can be spread and
2) what are the impacts or consequences in the event that it does spread. 
Knowing the answers to these questions will help you choose a suitable plant and prevent a garden plant from becoming an unwanted garden escapee.
If you would like further information on bluebell creeper please contact Kate Williams, Project Officer with the South Gippsland Landcare on 03 5613 5973 or email katew@wgcma.vic.gov.au For more information regarding the Parks Victoria weed control program please contact the Parks Victoria office at Foster on 03 5683 9000.

Don’t let gorse get a grip!

Ask anyone from north central Victoria or Tasmania what gorse is and they will probably tell you that it’s an absolute nightmare. Introduced to Australia in the early 1880’s, gorse is an extremely spiny shrub growing to 2.5m tall. Throughout the year gorse flowers bright yellow flowers shaped like those of a pea or bean, in Victoria flowering peaks in March to May, then again in July to October. The plant has negative impacts on grazing/cropping, native vegetation, land values and forest management. Gorse also acts as a fire hazard and harbor for pest animals. With this in mind it’s no wonder that gorse is classified as one of the 20 Weed of National Significance. In South Gippsland gorse is only found in relatively isolated areas at low densities. This is largely due to present climatic conditions in the region not being favored by the plant. In saying this, you might be wondering why I’m writing about a weed that is, for the most part, not found in South Gippsland. The answer - based on future climate modeling for Victoria, a very high potential exists for gorse to grow throughout the South Gippsland region (Department of Primary Industries 2008).

The old saying ‘prevention is better than a cure’ is highly relevant and should be exercised in dealing with gorse as with any other weed. Having worked in gorse infested areas north of Melbourne near Kilmore Victoria I know first hand the devastating impacts gorse can have. Left untreated it binds together to create an impenetrable mass that could take years or decades to eradicate. Decades may sound like I’m exaggerating but it’s the hard truth with plants living up to 30 years, producing an estimated 400million seeds/ha that can remain viable in the soil for at least 25 years. This information should therefore be seen as an opportunity to actively eradicate and manage gorse now in order to eliminate the high costs associated with managing established infestations. If you have gorse on your property and would like some advice on using best practice management methods or to obtain a free copy of the National Gorse Best Practice Manual please contact the South Gippsland Landcare Network by following the Contacts link on this web site.

Kate