How to kill broad leaf weeds in your lawn and stop them coming back

Learn how to kill broadleaf weeds in your lawn and stop them coming back. Our two-step Bow & Arrow and Spartan program breaks the weed cycle, prevents new weeds and reduces chemical spraying long term.

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Tired of spraying weeds in your lawn, only to have them keep coming back? The problem is that killing the weeds you can see doesn't stop new ones from growing. In this article, we'll explain a simple two-step approach that controls existing broadleaf weeds and prevents new weeds from germinating. It's a great way to break the weed cycle, keep your lawn weed-free for longer and significantly reduce the amount of spraying you'll need to do in the future.

The secret isn't just killing weeds. It's stopping them coming back.

You've sprayed the weeds in your lawn, they've died off and everything looks great.  Then, a few weeks later, they're back again. Maybe you've sprayed and haven't got much of a result at all. Sometimes it feels like you're constantly spraying, without ever really getting on top of the problem.

It's something we hear from customers all the time.

Some people struggle to get good results from spraying in the first place. Others get great results, only to have another crop of weeds appear a few weeks or months later. The problem is that most people are only dealing with the weeds they can see.

While spraying might kill the weeds already growing in your lawn, there can be thousands of weed seeds sitting in the soil, waiting for the right conditions to germinate.

As soon as they do, you're back to square one.

The good news is that there's a much better way to approach lawn weed control. Rather than continually spraying weeds as they appear, you can control the existing weeds and prevent many of the new ones from growing in the first place.

And that's where you start to break the weed cycle.

A two-step approach to lawn weed control

The approach involves two different types of weedkiller that do completely different jobs.

Step 1: Kill the weeds already growing with a Selective herbicide such as Bow and Arrow

Bow & Arrow is a selective post-emergent herbicide for broadleaf weeds. Post-emergent simply means it controls weeds that have already germinated and are growing in your lawn. It's particularly effective on many common broadleaf lawn weeds, including creeping oxalis, clover and bindii.

The benefit of using a selective herbicide is that it targets susceptible weeds without killing your lawn, provided it's suitable for your turf variety and applied according to the label.

There are other selective herbicides for other types of weeds in lawns. This article primarily focuses on broadleaf weed control. If other weeds are invading your lawn, you will likely find an alternative herbicide to tackle them. Regardless of the type of weeds in your lawn, the concepts raised in this article remain true: Always follow up your weed control efforts with a pre-emergent herbicide to stop the weeds from coming back. 

Step 2: Stop new weeds growing with Spartan

Spartan is a pre-emergent herbicide.

Unlike Bow & Arrow, Spartan doesn't control established weeds. Instead, it works in the soil to prevent susceptible weed seedlings from germinating. It's particularly useful for preventing common grassy weeds such as Winter Grass, Summer Grass and Crab Grass, along with certain other weeds listed on the product label.

The difference is simple: Bow & Arrow kills the existing broadleaf weeds. Spartan helps prevent the next lot of weeds from growing.

It's the combination of the two that makes this approach so effective.

Your step-by-step weed control program

You don't need to wait for a particular season to get started. If you've got broadleaf weeds growing in your established lawn, you can begin controlling them now, provided conditions suit the product directions.

Here's the program we recommend considering.

When	What to do	Why
Week 1	Spray existing broadleaf weeds with Bow & Arrow	Controls the weeds already growing
Week 4	Apply a second Bow & Arrow treatment if required	Tackles persistent weeds that survived the first application
After existing weed treatment	Apply Spartan pre- emergent herbicide	Prevents susceptible new weed seedlings from establishing
Every 12 weeks for the following year	Renew Spartan protection, subject to label directions	Maintains prevention across the changing seasons
Ongoing	Remove or selectively treat occasional weeds	Keeps the lawn clean without constant spraying

* If you have weeds other than Broadleaf in your lawn, contact us for advice on alternative selective herbicides. The chances are, there is one to suit your requiements. 

Getting the most from the program

Start with Bow & Arrow, applying it evenly using a pressure sprayer at the label rate. Some weeds can take a couple of weeks to show a noticeable response, so don't assume the treatment hasn't worked just because they haven't died immediately.

For persistent weeds such as creeping oxalis, a follow-up treatment around three weeks later may be needed, where the label permits.Once the existing weeds have been controlled, apply Spartan separately and water it into the soil as directed. This is important because Spartan works in the soil, not on the leaves of existing weeds.

Continue preventative treatments at the appropriate intervals across the following year, checking the label rates, maximum applications and suitability for your lawn. The aim is to maintain protection as different groups of weed seeds become active.

Less spraying and less chemical use in the long run

One of the biggest benefits of this approach is that it can significantly reduce the amount of weed spraying you'll need to do in the future. Instead of constantly reacting to new outbreaks, you're preventing many of those weeds from establishing in the first place.

The products we've discussed are targeted herbicides, with specific uses and application requirements. They still need to be handled carefully, but the aim is to use the right products, at the right rates, rather than repeatedly applying chemicals without getting lasting results.

After a year of controlling existing weeds and preventing new ones, the number of weeds in your lawn should be considerably lower. And because fewer weeds are growing and producing seed, you're reducing the opportunity for the next generation to establish.

This doesn't mean you'll never see another weed. Weed seeds can blow in from neighbouring properties, arrive with birds or be carried into your lawn in other ways. Some weeds will inevitably get through. But instead of having a lawn full of weeds that needs spraying regularly, you'll only have the occasional weed here and there, which can usually be pulled out. 

The bottom line

Getting on top of lawn weeds doesn't have to mean constantly spraying. With the right approach, you can break the weed cycle and enjoy a cleaner, healthier lawn with much less ongoing effort.

If you're unsure where to start, give us a call on (08) 8298 0555 or drop into Paul Munns Instant Lawn at 356 Brighton Road, Hove. We're always happy to help you work out the best approach for your lawn.

Frequently asked questions

Why do weeds keep coming back after spraying?

Because most selective weedkillers only control the weeds already growing. They don't prevent seeds in the soil from germinating. Without preventative control, new weeds can appear within weeks.

What's the difference between Bow & Arrow and Spartan?

Bow & Arrow is a post-emergent herbicide that controls existing broadleaf weeds. Spartan is a pre-emergent herbicide that prevents susceptible weed seedlings from establishing. They perform different jobs and complement one another.

Can I start this program at any time of year?

Yes, you can start controlling existing broadleaf weeds whenever they're actively growing and conditions suit the herbicide. Spartan can then be incorporated into your program, although applying it before each weed's main germination period gives the best preventative results.

How often should I apply Spartan?

A seasonal program, approximately every 12 weeks, can be considered where weed pressure is high. However, application frequency must comply with the product label, including maximum rates and intervals. After 4 x applications across a year, it is unlikely that you will need to continue using Spartan, as the weed cycle will have been broken. 

Will Spartan also prevent Winter Grass and Summer Grass?

Spartan is effective against a range of annual grassy weeds, including Winter Grass, Summer Grass and Crab Grass, when applied before germination. It can also help with certain other weeds, but it won't prevent every broadleaf weed species.

Do I need a pressure sprayer?

A pressure sprayer is strongly recommended. It gives you better control over the amount of chemical applied and more consistent coverage than many hose-on applicators.

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