
There are many varieties of Oxalis, known by common names such as: Soursob, Purple Oxalis, Wood Sorrel, Creeping Oxalis, and more.
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 the greatest concern as weeds.
Oxalis is often mistaken for Clover, while they both can have a similar appearance with trifolate sectioned leaves, Oxalis can be easily distinguishable by having Heart Shaped Leaves compared to the Oval Shaped and Serrated Leaves of Clover.

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 it 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 out-fight 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 herbicide when a lawn is infested.
When a garden or other area is affected with oxalis, the use of a non selective herbicide like Glyphosate is the best option to eliminate the weed and it's root system.
If 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 cookie.
Highly respected Australian turf and plant breeder Todd Layt shares expert lawn care advice with homeowners on The Lawn Guide.