How to Get Rid of Weeds in Your Lawn

For the home gardener, weeds can cause no end of problems. They’re some of the most persistent and determined plants in nature, often surviving in the most barren of soils. Weeds compete for valuable nutrients, light and moisture and can harbour a wide range of pests and diseases that spread throughout the garden.

Weeds germinate from seeds that arrive in your garden in various ways, such as sticking to your shoes, attaching to your clothes and being carried in by birds or the wind. Often, simply cultivating the soil can bring seeds to the surface, where they’ll germinate, even if they have been dormant for years.

Learn how to get rid of these pesky plants with our guide.

Effective weed control methods

Mulch

You can use mulch to smother existing weeds or stop new ones from emerging. Mulch comes in various organic forms, including straw, pea straw, newspaper, and organic weed mats. If using organic materials, apply a thick coat over the bare soil. Organic mulch also has the added benefit of adding nutrients to the soil.

Overseeding

Simply outplant weeds with desirable shrubs, flowers, or grass seeds. Tilting the competition in your favour crowds out light and space, making it less likely for weeds to take hold.

Removing flower heads

Prune or pull the weed’s flowers to prevent it from producing seed and restarting the cycle. This method is suitable for small patches but less effective for large areas.

Weed killers

Spray a systemic weed killer to get down to the root of the problem. These weed killers typically require active green growth and get absorbed into the plant’s system for effective eradication.

If you want to kill lawn weeds while keeping the grass intact, choose a selective herbicide that removes broadleaf weeds, such as dandelion, daisies, clover, creeping oxalis, hydrocotyle, selfheal, speedwell, dock, plantain, and Onehunga weed. You can also use weed killer for spot treating weeds in driveways and paths.

How to effectively spray a lawn with weed killer

Spraying herbicide in windy conditions is wasteful and ineffective. The wind can cause the spray to drift onto plants you don’t want to kill and give you spotty coverage on the plants you do.

Weed killers don’t get more effective when you double the concentration, so stick to the label instructions.

Rain reduces the effectiveness of herbicides. If it’s been raining, wait at least 5 hours before treating your lawn.

Spraying safety guidelines

ALWAYS follow the manufacturer’s instructions on mixing and using the chemical. They’ve worked out what you need based on good and responsible practice. Avoid mixing different herbicides together.

Dispose of empty containers according to the manufacturer’s instructions.

If the name of the chemical on the container is illegible, dispose of it as it has likely become unstable.

Like most things, herbicides have a shelf life; avoid using them a few years past the manufacturing date, as they will likely become ineffective.

Keep a separate set of equipment solely for measuring and mixing chemicals. Store them well out of reach of children.

Wear protective clothing, PVC gloves, and a respiratory mask when mixing and spraying lawn chemicals.

Keep out of the reach of children.

If poisoning occurs, follow the first aid instructions on the bottle and seek medical attention.

Call the New Zealand National Poisons Centre for 24-hour poisoning advice: 0800 764 766

How to maintain your sprayer

Remove and clean the nozzle after each use, as this is where debris tends to accumulate.

Leaving unused chemicals in a container creates a health hazard; dispose of them immediately.

Wash the sprayer thoroughly with cold water and detergent, ensuring that you run the water right through the spray lance as well.

If your sprayer has a filter, regularly check and clean it for optimal performance.

Keep separate sprayers for weed killers and insecticides, and clearly label them for identification.

Weeding tips for lawn grass and gardens

Lawn weeds

Here are some handy tips for weeds in your lawn:

Mowing over dock and dandelion won’t remove them as they continue to regrow from a long taproot. You’ll need to spray or dig out the plant by the root.

If you have a large-scale invasion of these broadleaf weeds, the best control is a broadleaf weed killer.

To get rid of Onehunga weed, which produces annoying prickles, use weed killer when it flowers in spring.

Use a fertiliser weed killer to feed your lawn while eliminating unwanted weeds in the grass.

Garden weeds

Keep your vegetable garden weed-free with these tips:

By regularly hoeing through the soil in your garden, you’ll lift smaller weeds out by the roots.

If you’re leaving your vegetable garden empty for a season, plant a cover crop like lupins or mustard. These crops dig through the soil and will smother any weeds tempted to make an appearance.

Prevent unwanted weeds from growing around your plants by installing a weedmat or ground cover.

Types of weeds

While some weeds are relatively harmless, many fall under the category of noxious weeds. Noxious weeds endanger not only our native forest, but also pasture and precious wetlands. You can effectively remove most weeds by hand or with a weed killer.

Annual weeds

Annual weeds will grow, flower and produce seed within a season or even a few weeks. It’s best to control these before they have the chance to produce weed seeds.

The most common annual weeds are Sorrel, Scarlet Pimpernel, Cress, Nettle and Fat Hen.

Perennial weeds

Perennial weeds are tougher to get under control, as they can multiply through seed or root division. These weeds have a taproot (main root) that supports the plant; you need to fully remove this to prevent regrowth.

If you want to remove these with a weed killer, you’ll usually need to apply it several times, especially on oxalis and onion weeds that have multiple bulbs that lie dormant.

Weeds that fall under this category include Buttercup, Thistle, Dock, Ink weed, Oxalis and Stinging Nettle.

Woody weeds

Woody weeds grow into medium-to-large shrubs and can strangle the positive plantings in your garden. If you plan to use weed killer, we recommend removing all of the top green growth first. Wait for fresh growth to reappear, then spray. Once no new growth appears, you can remove the roots.

In this category, you’ll find Gorse, Woolly Nightshade, Tree Lupin, Castor Oil Plant and Poroporo.

Climbing weeds

Climbers spread quickly and are tenacious thanks to their ability to grow from a small underground root.

Once a climber has taken hold, you need serious elbow grease to get rid of it. Spraying these weeds can risk killing desirable plants, so removal requires a managed approach. It can be tough to find an instant solution; you might need to remove smaller new growth regularly.

Find the start of the plant. In some cases, climbing weeds have runners that form new vines.

Cut all these vines off at the base, so that the ends of the plants die off.

Wait until the ends have dried before pulling them down. This makes it easier to remove them and minimises the damage to the host trees.

The stumps will try to regrow. You can either:

Remove the weed by digging it up.

Wait for new growth to appear, then apply weed killer.

Plants that fall under this category include Blackberry, Smilax, Morning Glory, Old Man’s Beard, Banana Passion Fruit, Climbing Dock, Honeysuckle and Convolvulus.

Easily eliminate lawn weeds with Trade Tested

Keep your grass comfortable, healthy, and looking great with Trade Tested’s lawn care products. As one of New Zealand’s biggest online gardening stores, we help Kiwis across the country maintain their outdoor areas from summer to spring.

Shop our lawn weed killers and sprayers today. Have a question about any of our products? Contact our friendly team, who’ll be happy to help!

Hear our customers’ thoughts

Tui Lawnforce Weedkill Fertiliser

“The change in the lawn was noticeable within two weeks, weeds disappeared, and the grass thickened and greened up. A great product which reminds me to order more.”

Kiwicare LawnPro Turfclean Ultra Concentrate 800ml

“Easy application. Has worked well on a whole range of different weeds in our large lawn.”

Tui Lawnforce Weedkill Fertiliser

“I used this on my lawn because it had lots of weeds. It was very easy to spread the granules. In just a week, the weeds started dying, and the grass became much greener. It's amazing to see two results from one product. I highly recommend it if you want a nicer lawn with less work.”

Frequently asked questions

Can I get rid of weeds without killing the grass?

Yes, you can target weeds without harming grass by using selective herbicides designed for lawns, which kill broadleaf weeds but leave grass intact. Another option is hand-pulling or using a weeding tool to completely remove them by the root. Keeping your grass healthy with proper mowing, watering, and fertilising also helps prevent weeds from taking over.

How do I get rid of lawn weeds naturally?

Natural methods include hand-pulling weeds and mulching garden edges. Maintaining a thick, healthy lawn through overseeding and proper mowing also reduces bare patches where weeds can grow.

What’s the best way to remove weeds from a large area?

The most effective way to remove weeds from a large lawn is to use a weed killer and sprayer. For large gardens, use sheet mulching or a weed mat; both techniques effectively remove weeds without damaging other plants.

Can I compost lawn weeds?

Like any green growth, lawn weeds can benefit your compost bin. However, high temperatures are necessary to kill off weed seeds, so only include seed heads if your compost bin is hot enough to do so. Chop or shred woody stems and vines before adding them to the compost. Leave out any weeds that have been sprayed with a weed killer chemical.