As we near winter, the soil temperature decreases. Our garden beds begin to slow their growth, and the plants that thrive thru Spring and Summer, come to the end of their growth cycles, and begin more dormant periods. Lawns need less mowing, and thankfully so, because motivation to get out in the garden is definitely decreased in sync with the drop in temperature. However, some plants are just begining their period of dominance. Some may even be undesireable, case in point, Oxalis in your lawn. Often considered by some, to be a weed, Oxalis actually has many benificial properties, some types are grown for their beautiful flowers in winter, others for their leaf shape and pattern like Oxalis tetraphylla, some people even harvest it as an additive to a warm winter beverage. If a warm cup of Oxalis, isnt your cup of tea, then here are some methods of control.
There is a great misunderstanding of the ‘Weeds’ we see in our gardens. Many wouldn’t consider Oxalis as a weed, in fact, many keen gardeners have a pot or two that they’re very fond of. An easy plant to care for, and a lovely show during the cooler months. What defines a weed is totally based on perception. If you don’t want it in your garden, then it is a weed. If it is choking, or stealing nutrients from a plant you wish to grow in your garden, it is a weed. There is also a list of prohibited weeds of Victoria . These are weeds that are introduced, damaging to the environment, and in small enough density that there is a reasonable opportunity for eradication or control.
Oxalis is commonly perceived as a weed because of its invasive nature. Popping up through the grass, the oxalis leaves break up the uniformity of a well manicured lawn. Running through a garden bed, the bulbous plant can often steal valuable nutrients from surrounding plants. Over winter when nutrients are scarce, this can lead to your favoured plants losing out on the food they need to rebound in Spring. Often mistaken for clover, these two are often controlled in a similar manner. Weed management is always more successful with a multi-pronged strategy. Also known as Integrated Weed Management. These include, but are not limited to; physical, cultural, mechanical, chemical and biological.
To break that down, in relation to oxalis;
Physical: To observe and remove by hand, as the leaves emerge, before flowering. Control in this method is often painstaking, and fastidious. One must be careful to remove not only the leaves and stems, but also the bulbs that sit underground. The main problem encountered with removal of Oxalis is that the delicate stem often breaks, leaving multiple bulbs underground ready for the next opportunity to pop up.
Cultural: Cultural methods of weed control include promoting the growth of competing crops, to lower the available space for weeds to grow. Working on the oxalis in your lawn, a cultural control would be to keep feeding your lawn through the autumn months, creating a healthy thick lawn before the more dormant winter months, won’t eliminate the oxalis, but it will aid in its eradication.
Mechanical: As well as feeding and treating your lawn over the months preceding the growth of Oxalis, frequent mowing can also improve your chances of control. Regular mowing not only improves the health and vitality of your lawn, it will also contribute to weed control. A handweeder can also be quite effective:
Biological: Did you know that Oxalis is edible? Described as having a sour and refreshing taste due to its high levels of oxalic acid, records of people eating oxalis go as far back as King Henry VIII. As well as human appeal, it is also a favourite of Chickens, those lucky enough to have them, will know, the young leaves are a crowd favourite among the chooks.
Chemical: Preferably a last resort, chemical controls for Oxalis are many and varied. When dealing with oxalis in a lawn, selective herbicides are a very handy weapon. These target the wider leaf shape of the oxalis, and have minimal impact on the narrow leaves of the lawn. The problem with this method is that it’s not a uniform solution; a Buffalo lawn, for example, has a wide enough leaf that the herbicide is not as selective, and a Buffalo specific herbicide is recommended. If you’re not sure what type of lawn you have, feel free to bring in a sample to our knowledgeable staff at the Information Counter, and we will find something specific to your needs.
There are also non selective herbicides that will work when removed from a pathway or a dormant garden bed, however, these often have residual qualities, meaning you may not be able to grow anything in that spot for up to 12 months. Select a herbicide that is non residual. Natural herbicides are made from naturally occurring chemicals extracted from plants and minerals. These have a lesser impact on the environment, and usually have the benefit of being less toxic to humans and animals. Always read the label and follow directions when using chemicals.