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Weed Killer Finder

We’ll show you how to compare weed killer to find the right herbicide for your garden.

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Tim Falk
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Best Weed Killers

Best Rated Weed Killer Brand: Roundup

The most effective weed killer as voted by Aussies is Roundup. It also rated well for ease of use, which helped it take this year's Finder Award.

Key facts about comparing weed killer:

  • Is your lawn being taken over by weeds? If you want to regain control of your yard, you’ll need to find a reliable weed killer to eradicate those pesky unwanted plants.
  • The right weed killer for you will vary depending on the type of weed, where it's growing and whether you want to kill the weed's above-ground parts only or eliminate its roots as well.

What is a weed?

A weed is a plant that grows somewhere it isn't wanted. Weeds offer no value at all to your lawn, and they steal water and other nutrients from your lawn and plants.

Many weeds also spread easily and can be quite invasive, ruining the look of your otherwise well-manicured lawn. Common weeds in Australia include clover, dandelion and the dreaded bindi.

Weed killers are herbicides that use chemicals to attack and kill weeds. However, the way they work, and the parts of the plant they target, can vary from one product to the next.

What types of weed killer are available?

Before you can start shopping for a weed killer, it's important to understand that weed killers work in different ways. As a result, the right product for you will depend on the weed problem you need to tackle.

Pre-emergent weed killers stop weeds from germinating, while post-emergent products kill weeds once they appear through your soil. You can also differentiate between weed killers based on their method of operation:

  • Contact weed killers. These herbicides are designed to kill the portion of the plant they come in contact with. They're fast acting, widely available and typically a good choice for annual weeds, but they may not be enough to completely destroy a weed.
  • Systemic weed killers. These products are absorbed by the weed and make their way into its root system. They inhibit the growth of the plant and slowly kill it off, so they're useful for killing perennial weeds.
  • Residual weed killers. Residual weed killers are long-lasting herbicides designed to create a protective barrier to stop weeds from growing. However, using them means you won't be able to plant anything in the same area for months, so these products are commonly used to tackle weeds that sprout up through cracks in paths or gaps between pavers.

Weed killers can also be selective or non-selective:

  • Selective weed killers. As the name suggests, these products will only target specific plant species. This means you can typically use them safely without having to worry about killing off your lawn, but be aware that some products should not be used on buffalo grass.
  • Non-selective weed killers. These products are designed to kill any plant they come into contact with. This means you need to use care when spraying to ensure that you only kill off the weeds you're trying to target.

How to compare weed killers

You'll need to consider several factors when deciding on the right weed killer for your needs.

The weeds you want to target

Are you targeting seasonal weeds or weeds that are a problem all year round? Are you trying to kill off an entire section of weeds or "spot kill" specific plants around your lawn? Do you just want to target the parts of the weed that are above the ground or kill off the entire plant?

Once you've answered these questions, you can narrow your choice down to a contact, systemic or residual weed killer and decide whether you want a selective or non-selective product.

How to apply

Check what you need to do to use the weed killer in your yard. Some products come in their own ready-to-use spray bottle, while others are sold as concentrate that you can dilute into a spray bottle with a weed wand.

Selective herbicides are also available in spray bottles you can attach directly to your hose or as granular products that can be sprinkled on your lawn.

Where it can be used

It's worth noting that many broadleaf weed killers will also affect buffalo grass, so check the label to find out whether a product is safe for use on your lawn. Also be sure to check whether a product is designed for lawn use or whether it's a residual weed killer designed to be used on paths and pavers.

Coverage

Check the label for a guide to the number of weeds you can expect to kill with one bottle or the maximum yard size a product is designed to cover.

Active constituents

If you're concerned about the safety of a particular product, check the label to find out what active constituents it contains. One of the most common ingredients is glyphosate, a non-selective and systemic herbicide.

Fertiliser

Selective weed killers will often also include fertiliser. This means they can be sprayed onto your lawn to kill the weeds you're targeting and also provide nourishment for your lawn at the same time.

Price

Prices vary depending on the type of weed killer you buy and how it is packaged. The price of 1L of weed killer concentrate ranges from approximately $7 to $30, while 750mL ready-to-spray bottles range from around $7 to $15.
When comparing two similar weed killers, remember to compare the price per 100mL to ensure a fair comparison.

How to control weeds without using chemicals

While you can overcome weed problems with weed killers, prevention is always better than a cure. There are plenty of simple things you can do to minimise the weeds in your lawn without having to reach for the chemicals:

  • Choosing the right grass. Some grasses are better than others when it comes to competing with weeds for water and nutrients. However, the right grass for your yard will vary depending on where you live, so ask your local garden centre for advice.
  • Looking after your lawn and garden. A healthy lawn will be better placed to compete with weeds for water and nutrients, so fertilise your lawn to keep it in the best possible shape. Laying mulch in your garden will also give weeds less of a chance to propagate.
  • Weeding by hand. It can be hard work, but weeding by hand or with a weeding tool will help you stay on top of your weeds and stop them from spreading.
  • Consider organic products. If you're worried about using a product containing chemicals produced in a lab, you can always consider using an organic weed killer. You'll find several products to choose from at your local garden store.

Three things to consider

There are a few other factors you should consider before buying weed killer:

  • Read the label. Under Australia's labelling requirements, products can be classified as exempt from poison scheduling or they must be a Schedule 5 or Schedule 6 poison. Schedule 5 poisons (look for the word "Caution" at the top of the label) have a low potential for causing harm, while Schedule 6 poisons (look for the word "Poison" at the top of the label) have a moderate potential for causing harm.
  • When to apply. Check the label for instructions on the best time to apply a product, such as on still rather than windy days and when there is no rain predicted.
  • Ask for advice. If you're unsure about the best approach for controlling weeds in your lawn or garden, don't hesitate to ask for help at your local garden centre. They'll be able to provide advice based on your situation and the growing conditions in your area.

Ready to start shopping? Check out our guide to the best weed killers.

Best rated weed killer brand award breakdown

Total Score Overall rating Value for Money Ease of use Effectiveness Smell
Roundup 7.94 4.40 4.02 4.48 4.48 3.71
Bunnings 7.81 4.27 4.04 4.35 4.20 3.71
Hortico 7.74 4.24 4.10 4.44 4.12 3.62
ALDI Gardenline 7.57 4.00 4.43 4.24 4.19 3.57
Other 7.53 4.08 4.08 4.17 4.13 3.71
Yates 7.37 4.06 3.71 4.41 3.98 3.55
Dicamba M 7.23 3.88 3.38 4.25 4.00 4.13
Slasher 7.22 3.93 3.13 4.53 3.87 4.20
RichGro 7.20 3.88 3.88 4.25 3.83 3.63
Data: Finder Retail Brand Survey, 2020, Kantar. Metric out of 5 stars unless indicated. Methodology and more info. Kantar logo

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