Despite being a natural part of Australia’s ecosystem, weeds can do much damage when left to their own devices.
WATCH: Graham Ross on stopping leaves from taking over your garden
In fact, the six most common weeds cover an area three times the size of Tasmania, which shows how fast these plants can spread. What’s worse is that 72 per cent of the weeds in Australia today were accidentally introduced as ornamentals.
So what is a weed?
In a previous interview with Better Homes and Gardens, Aimee Freimanis, the Program Manager of the Gardening Responsibly Initiative, says: “The definition of a weed is a plant in the wrong place. Nobody wants weed in their garden.”
Weed groups
There are four types of weed groups. Knowing which group your garden weeds belong to can help with your control strategies.
- Annuals – weeds that complete their life cycle in one year.
- Biennials – weeds that complete their life cycle over two years
- Perennials – live for more than 2 or 3 years.
- Woody plants – trees, shrubs etc.
How weeds spread
Weeds need more than a seed to germinate and spread long distances. The most common way germs (or their seeds) are spread is through the wind. Being carried along the water is another. Seeds can cling to the fur of animals and of course, people unknowingly spread weeds, too.
Weed prevention
If you have a garden, then at some point, you are going to have weeds. Instead of waiting for the weed to show its ugly head, it’s best to have some prevention strategies in place. Importantly, mulch is an excellent way to prevent weed growth. In fact, the book Garden Weeds by Bruce Morphett, he says: “A 50-100mm mulch layer will reduce weed growth by 70 – 100%.”
If you have weeds in your garden, you first need to identify the type of weed to find out the best way to control it.
We’ve compiled a list of Australia’s most common weeds and how to eradicate them.
Weed identification
1. Bindii (Soliva sessilis)
Type: broadleaved annual
Also known as “jo-jo,” bindii is a low-growing weed that produces small spiky burrs. These burrs hurt when stepped on or sat on.
Control tips: Hand-weeding the weed before the burrs appear can work, but it’s usually too late because they’ve already started germinating. Additionally, pre-emergent herbicides in early spring can help prevent bindii seeds from germinating.
2. Clover (Trifolium spp.):
Type: broadleaved perennial
Also known as white or Dutch clover, it’s a common weed with white flowers often appearing on lawns. While some intentionally cultivate clover for its nitrogen-fixing properties (it’s also great for the bees), it can become invasive and take over your whole lawn.
Control tips: If you want to remove it, hand pulling can be effective if the patch is small before it flowers. Spray with vinegar and a few drops of dishwashing liquid for established clover clumps. Or use a broadleaf herbicide formulated for lawns.
3. Capeweed (Arctotheca calendula)
Type: broadleaf annual
Capeweed is a broadleaf annual weed with yellow daisy-like flowers. It can spread rapidly if left unchecked.
Control tips: Hand-pulling capeweed can be effective for small patches if you get to them before the flowering stage. Avoid having bare patches of ground in late summer; the perfect space for growing capeweed. Once plants start seeding, they are easily spread. Herbicides that target broadleaf weeds are suitable for larger areas. For advice on herbicides for capeweed, visit the Department of Natural Resources and Environment Tasmania.
4. Oxalis (Oxalis spp.)
Type: Broadleaf perennial
Also known as sourgrass or wood sorrel, oxalis is recognisable by its clover-like leaves and small yellow or pink flowers. It can quickly establish itself in garden beds and lawns.
Control tips: Hand-pulling oxalis before it flowers is effective and recommended. You can also spot-treat with a broadleaf herbicide. Additionally, oxalis seeds need light to germinate, so adding a light later of mulch around flowers and plants can prevent the spread of oxalis.
5. Dandelion (Taraxacum officinale)
Type: broadleaf perennial herb
Dandelions are recognisable by their bright yellow flowers and fluffy seed heads. They have deep taproots and can be challenging to eradicate.
Control tips: Hand-digging is effective for small patches, but dandelions have deep taproots, making complete removal challenging. Older plants can regrow from missed root fragments. Herbicides formulated for dandelion control or a broad lead fertiliser can be used as a last resort.
6. Paspalum (Paspalum spp.)
Type: grass leaf annual or perennial
Paspalum is a grassy weed that can invade lawns, gardens, and other areas. It produces seed heads with distinctive spikelets.
Control tips: Mowing regularly and maintaining a healthy lawn can help control paspalum. Like most weeds, handweeding is the most effective method of removing Paspalum. However, herbicides labelled for grassy weeds or ‘paspalum killer’ can be used for persistent outbreaks.
7. Couch grass (Cynodon dactylon)
Type: grass leaf annual
Couch grass, or Bermuda grass, is a persistent warm-season weed. It can invade lawns and garden beds and is known for its tenacious underground root system.
Control tips: Couch grass is hard to eradicate. Frequent mowing can weaken couch grass. But the best way to get rid of couch grass is to stop it receiving sunlight. This can be done with landscape fabric or a thick layer of cardboard. Herbicides labelled for grassy weeds can be used, but control may require multiple applications. Glyphosate-based product is the most effective.
8. Caltrop (Tribulus terrestris)
Type: Annual
Caltrop, also known as bindii or cat’s head, produces sharp spiky burrs that can be painful when stepped on.
Control tips: Consistent hand-pulling is effective for small infestations. For larger areas, herbicides can prevent caltrop seeds from germinating.
9. Flaxlead fleabane (Conyza spp.)
Type: Annual
Fleabane is a weed with small daisy-like flowers that can spread and colonise disturbed areas.
Control tips: Fleabane can be controlled by regularly mowing and removing flower heads before producing seeds. Herbicides labelled for broadleaf weeds can also be used.
10. Thistles (Cirsium spp.)
Type: Annual to biennial
Various thistle species, such as Scotch thistle and slender thistle, can be found in Australian landscapes and can be challenging to control due to their spiky leaves.
Control tips: Thistles can be managed by hand-pulling or cutting off flower heads before they seed. Herbicides labelled for thistle control are effective, but control may require multiple applications.
11. Malva parviflora aka Mallow (Malva spp.)
Type: Annual or perennial
Mallows are broadleaf weeds with lobed leaves and small pink or purple flowers.
Control tips: Hand-pulling is effective for small infestations. For larger areas, herbicides labelled for broadleaf weeds can be effective on young plants.
12. Dwarf nettle (Urtica urens)
Type: Annual
Dwarf nettle is a stinging weed with small leaves that can cause skin irritation upon contact.
Control tips: Wearing gloves and protective clothing, hand-pulling or carefully cutting dwarf nettle can help control it. Herbicides may not be very effective due to its stinging nature.
13. Flatweed or Catsear (Hypochoeris spp.)
Type: Perennial
Flatweeds have basal rosettes of leaves and produce yellow dandelion-like flowers.
Control tips: Hand-pulling or mowing can help control flatweed. Herbicides labelled for broadleaf weeds can be used for larger infestations.
14. Paterson’s Curse (Echium plantagineum)
Type: Biennial or annual
Also known as Salvation Jane, this invasive weed produces purple-blue flowers and can dominate pastures.
Control tips: Herbicides labelled for broadleaf weeds can be used to control Paterson’s curse. Regular monitoring and early treatment are essential. Find out more about controlling Patterson’s Curse.
15. Soursob (Oxalis pes-caprae)
Soursob is characterised by its clover-like leaves and bright yellow flowers. Unlike Oxalis, soursob produces underground bulbs.
Control tips: Hand-pulling can help control soursob, but removing the bulbs at the old bulb stage before new bulbs start to form is also important. Herbicides labelled for broadleaf weeds can also be used.
Best tools for hassle-free gardening
1. Swift RM18 robotic mower, $799.99, Kogan
This robot mower is auto-charging, self-propelled and suitable for up to 600m². Additionally, this mower comes with a PIN Code for theft protection.
2. Built Tray Galvanised Wheelbarrow, 80L, $125, Amazon
The Built galvanised wheelbarrow, with its 80-litre capacity, is a heavy-duty and reliable gardening tool designed to make tasks easier with features like a galvanised steel tray for durability, a powder-coated steel frame for resistance against abrasion and corrosion, and comfortable, easy grip handles, ensuring it stands up to the demands of heavy-duty work.
Spear & Jackson planting and weeding Knife, $50, Amazon
The Spear & Jackson planting and weeding knife is a versatile gardening tool with a mirror polished stainless steel head designed for minimal soil adhesion and rust resistance. It features a serrated edge for cutting through thin roots, a pronged blade for effective weed and daisy removal.
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