How to Tell Lawn Weeds Apart: Broadleaf, Grassy, and Sedge
Most weeds that turn up in New Zealand lawns fall into one of three rough categories, and figuring out which one you’re looking at is usually the fastest way to narrow down an identification.
Broadleaf weeds have wider, often rounded or oval leaves that look obviously different from grass blades — think clover or dandelion. Grassy weeds are trickier because they genuinely are grasses, just not the turf species you want, so they can blend in until they start seeding, changing colour, or growing in a noticeably different pattern (couch and paspalum are common examples). Sedges look grass-like at a glance but have a triangular stem instead of a round or flat one, which you can usually feel by rolling the stem between your fingers.
This three-way split won’t identify every weed on its own, but it’s a useful starting point before you get into specifics.
Common Broadleaf Weeds in New Zealand Lawns
Clover
White clover is one of the most widespread lawn weeds in the country, recognisable by its three (occasionally four) rounded leaflets and white flower heads. It spreads via creeping stolons along the soil surface, which is why a small patch can expand across a lawn fairly quickly if left alone.
Dandelion and Catsear
Both grow as a low rosette of leaves with a yellow flower on an upright stem, which makes them easy to confuse with each other. Dandelion leaves are more deeply jagged, while catsear leaves tend to be softer and more rounded with fine hairs. Both have a long taproot, which is part of why pulling them by hand often leaves enough root behind for the plant to regrow.
Creeping Buttercup and Creeping Oxalis
Creeping buttercup has three leaflets and shiny yellow flowers, and spreads through creeping stems that root as they go, often favouring damp, poorly drained patches of lawn. Creeping oxalis also has three leaflets (sometimes confused with clover at a glance) but tends to form denser mats and can be more persistent once established.
Plantain (Broad- and Narrow-Leaved)
Plantains grow as a flat rosette of leaves close to the ground, which lets them survive fairly low mowing heights. Broad-leaved plantain has wide, oval leaves, while narrow-leaved plantain has longer, more strap-like leaves. Both send up thin, upright flower spikes from the centre of the rosette.
Hydrocotyle
Hydrocotyle covers a group of related low-growing weeds with small, rounded, slightly scalloped leaves that can form dense mats in damp or shaded lawn areas. There are several similar species in this genus, and they’re generally considered among the more persistent lawn weeds to control once established.
Onehunga (Prickle) Weed
This low-growing weed has finely divided, almost fern-like leaves and produces small, sharp seed burrs that are genuinely painful underfoot — often the first sign homeowners notice, before they spot the plant itself. It tends to favour drier, sunnier lawn areas.
Common Grass Weeds (Weeds That Look Like Grass)
Couch, Kikuyu, and Paspalum
Couch is a rhizomatous grass that spreads underground and can be difficult to fully remove once it’s mixed into a lawn, since broken rhizome fragments can resprout. Paspalum forms dense clumps joined by short, stout rhizomes and is often noticeable because its seed heads look and feel different from fine lawn turf. Kikuyu is a vigorous, coarse-bladed runner grass that can quickly outcompete finer lawn species if it establishes.
Poa Annua (Annual Poa)
Poa annua (annual poa) is a small grass with light, yellowish-green leaves that often stands out against darker-green lawn turf, especially in cooler months when it seeds prolifically. It’s an annual, so a fresh flush can reappear from seed even after you’ve dealt with an earlier patch.
Yarrow and Other Persistent Perennial Weeds
Yarrow is worth calling out on its own because it’s unusually tough: it tolerates drought, poor soil, hard mowing, and even many common herbicides, thanks to waxy leaves that are harder for sprays to penetrate. It forms fern-like, feathery leaf clusters that can spread low and wide under regular mowing, and its underground rhizomes mean it often needs more than one treatment — sometimes more than one season — to fully clear from a lawn.
Are Any of These Invasive in New Zealand?
A few lawn and pasture weeds in New Zealand are considered more broadly invasive beyond just home lawns — for example, weeds like old man’s beard, gorse, and blackberry are more of a concern in waste areas, bush margins, and pasture than in mown turf itself. Most of the weeds covered above (clover, dandelion, plantain, buttercup, oxalis) are common and widespread rather than classified as high-risk invasive species, though they can still be persistent and difficult to fully remove from a lawn once established.
What Kills Lawn Weeds Without Killing the Grass?
Selective herbicides are formulated to target broadleaf weeds (or specific weed groups) while leaving most common lawn grass species largely unaffected, which is different from a general weedkiller that would damage grass too. That said, results vary a lot by weed type — some weeds, like yarrow, are naturally more tolerant of common herbicides and may need repeated applications or a penetrant additive to get good coverage through waxy leaves.
Because product formulations and local regulations change, it’s worth checking current label guidance or a local garden centre for a product suited to your specific weed and grass type, rather than relying on a one-size-fits-all recommendation. Keeping the lawn itself healthy and dense — through regular feeding and overseeding bare patches — also makes it harder for new weeds to establish in the first place, which is a useful complement to any chemical treatment.
Identifying Weeds Without Guesswork (Apps, Photos, and Local Resources)
If you’re not confident identifying a weed from a written description, a few options can help confirm it. Some gardening retailers offer online “problem solver” tools where you answer a few questions about the weed’s appearance and growing conditions to get a likely identification. Photo-based plant identification apps can also give a reasonable starting point, though they’re not always accurate for grass-like weeds that look similar to each other. For trickier or more persistent cases, university-run weed databases and local garden centres tend to be more reliable than a quick photo match.
Regional Differences: Why Your Weeds May Vary by Area
Which weeds show up in a lawn depends heavily on local climate, soil, and turf type, so the mix you see will differ from one region to another — even within the same country. Warmer, more humid regions tend to favour different weed species than cooler ones, and the same is true internationally: our guide to Central Florida lawn weeds covers a quite different set of broadleaf, grassy, and sedge weeds suited to that warmer climate and turf types like St. Augustine and Bahia grass, which illustrates how much regional conditions can change the picture.
FAQ
What are the most common lawn weeds in New Zealand? Clover, dandelion, catsear, plantain, creeping buttercup, creeping oxalis, and yarrow are among the more commonly reported weeds in New Zealand home lawns, alongside grass weeds like couch and poa annua.
What kills weeds on a lawn without killing grass? Selective herbicides are designed to target weeds like broadleaf species while leaving most lawn grasses largely unaffected, though effectiveness varies by weed and product. Checking current label guidance for your specific situation is the safest approach.
Can I identify weeds using a photo in New Zealand for free? Photo-based plant ID apps and some retailer “problem solver” tools can give a free starting point for identification, though they’re not always reliable for grass-like weeds. University weed databases are a more dependable backup for confirming a tricky identification.
What are some of the invasive weeds in New Zealand? Invasiveness classifications generally apply more to weeds affecting bush, waste areas, and pasture (such as old man’s beard, gorse, and blackberry) than to common lawn weeds like clover or plantain, which are widespread but not typically classified the same way.