How To Kill Oxalis | Soursob | Wood Sorrel
There are many varieties of Oxalis, known by common names such as: Soursob, Purple Oxalis, Wood Sorrel, Creeping Oxalis, and more names.
With over 800 known varieties of Oxalis, and over 30 of those in Australia, not all are weeds, and some may even be beautiful ornamental plants. For the purposes of this articles we'll concentrate on those varieties of Oxalis which are of the greatest concern as weeds.
Oxalis or Clover
Oxalis is often mistaken for Clover, while they both can have a similar appearance with trifoliate sectioned leaves, Oxalis can be easily distinguishable by having Heart Shaped Leaves compared to the Oval Shaped and Serrated Leaves of Clover.
Oxalis consuming a lawn
Invasiveness of Oxalis
All Oxalis weeds in Australia are considered highly aggressive, and should be eliminated completely from our lawns and gardens in order to be controlled. An infestation can occur in almost any environment.
Oxalis can have creeping stems that knit into the layers of the lawn and its roots, and sets down numerous corms, making Oxalis very difficult to hand-pull as a means of eradication.
The picture above illustrates Oxalis completely overtaking a Couch lawn. The aggressiveness of the Oxalis is highly increased due to poor lawn health. In this situation, the Couch lawn is exposed to too much shade to ever obtain optimum health. As a result, the Oxalis is free to aggressively spread and easily fight and win against a highly weakened lawn.
Oxalis is very difficult to remove, and may need 2-3 treatments over a period of weeks with a selective Oxalis herbicide when a lawn is infested.
When a garden bed or other non-lawn area is affected with Oxalis, the use of a non selective herbicide like Glyphosate is the best option to eliminate the Oxalis weed and its root system. Just be very careful with Glyphosate - as this non-selective herbicide will kill any lawn or plant it comes into contact with. Use Glyphosate carefully.
If Oxalis problems still persist, and the weed is proving difficult to eradicate, try switching herbicide brands and types, or consult a Professional and Licensed Weed Control Contractor. Oxalis is one tough weed, and hiring a professional weed spraying contractor may be the overall easiest, quickest and cheapest method to permanently remove Oxalis from our lawns.
Just realise though, that even with professional weed spraying or if the homeowner is spraying Oxalis themselves - that more than one treatment is likely necessary, and that we should expect to treat Oxalis again over the next couple of years until it is fully eradicated from our lawns.
Be sure not to forget to remove all traces of Oxalis from garden beds as well.