--- title: Nutgrass canonical: https://gardensuperstore.com.au/problem-solver/nutgrass/ dateModified: 2026-08-07 09:52:56 summary: "Nutgrass (Cyperus rotundus L.) is a persistent warm-season sedge that spreads through underground rhizomes and tubers. Identify its glossy leaves, three-sided stems and brown flower heads, then manage actively growing plants and reduce overwatering." type: article keywords: [Nutgrass, Cyperus rotundus L.] --- # Nutgrass > Nutgrass (Cyperus rotundus L.) is a persistent warm-season sedge that spreads through underground rhizomes and tubers. Identify its glossy leaves, three-sided stems and brown flower heads, then manage actively growing plants and reduce overwatering. *Cyperus rotundus L.* Nutgrass, also called purple nutsedge, is a perennial sedge rather than a true grass. It grows from underground tubers (nutlets) connected by a network of wiry rhizomes, which is why pulling the visible shoots rarely gets rid of it. Each tuber can produce new shoots and further tubers, allowing a single plant to spread into a dense colony over a season. The leaves are grass-like but distinctly V-shaped in cross-section and arranged in sets of three from the base, giving the stem a triangular feel when rolled between your fingers - a classic sedge trait ('sedges have edges'). Leaves are glossy, mid-to-dark green and narrower than most turf grasses, growing more upright and often noticeably faster than the surrounding lawn, so it stands out within a day or two of mowing. In summer it produces a flowering stem topped with a spreading cluster of small reddish-brown to purplish spikelets, followed by small brown seed. Below ground, chains of round to oval tubers, dark brown and about the size of a small pea to a marble, sit at the end of thin rhizomes, often clustered close to the soil surface but extending down 20-40cm. It's a widespread weed across Australia's warmer regions, thriving in the warm, moist conditions of spring through autumn and going dormant over winter when it dies back to the tuber. It's common in lawns, garden beds, vegetable patches and disturbed or poorly drained soil, and readily moves between sites in contaminated soil, pots or turf. Management relies on persistence rather than a single treatment. Because tubers can remain dormant in soil for years and regenerate after cultivation, hand-pulling or hoeing alone tends to spread rather than solve the problem, as broken tubers simply produce more plants. Effective control usually combines repeated removal of top growth to exhaust tuber reserves, improving drainage where waterlogging favours it, and targeted herbicide use timed to actively growing plants, following label directions for the specific situation (lawn, garden bed or vegetable area). ## How to identify - **Faster-growing tufts:** Bright to dark green, upright leaves that outgrow the surrounding lawn within a day or two of mowing, giving an uneven, patchy look. - **Triangular stems:** Roll a stem between your fingers - true grasses are round or flat, nutgrass is distinctly three-sided. - **Leaves in threes:** Leaves arise from the base in groups of three rather than the two-sided arrangement typical of grasses. - **Underground tubers:** Dig around an affected clump - small, round, dark brown tubers strung along thin rhizomes confirm nutgrass. This is the most reliable field check, since top growth alone can be mistaken for grass. - **Summer flower heads:** Reddish-brown to purple spikelet clusters on a triangular stalk appear over the warmer months. - **Common lookalike - true nutgrass vs. summer grass or paspalum:** These grasses can also grow quickly between mows but have round or flat stems and no underground tubers - dig down to check. - **Common lookalike - yellow nutsedge (Cyperus esculentus):** Similar growth habit but tubers form singly rather than in chains, and flower heads are yellow-brown rather than purplish. Positive identification may need a close look at the tubers and flower colour. ## Registered products we stock - [Sempra | Herbicide | Nutgrass Killer](https://gardensuperstore.com.au/sempra-herbicide-nutgrass-killer/) — Nufarm - [Tempra 750WG | Herbicide | Nutgrass Killer](https://gardensuperstore.com.au/tempra-750wg-herbicide-nutgrass-killer/) — PCT SureFire - [Monument Liquid | Turf Herbicide](https://gardensuperstore.com.au/monument-liquid-turf-herbicide/) — Syngenta - [Fusilade Forte 128EC | Herbicide](https://gardensuperstore.com.au/fusilade-forte-128ec-herbicide/) — Syngenta - [Passtox Clear | DSMA | Herbicide](https://gardensuperstore.com.au/passtox-clear-dsma-herbicide/) — Colin Campbell Chemicals - [Quali-Pro Nutmeg | Selective Herbicide](https://gardensuperstore.com.au/quali-pro-nutmeg-selective-herbicide/) — Adama - [Crab Grass & Clover Killer | Selective Weedkiller](https://gardensuperstore.com.au/crab-grass-clover-killer-selective-weedkiller/) — David Grays - [Gauntlet | Herbicide](https://gardensuperstore.com.au/gauntlet-herbicide/) — Adama - [Weedmaster Duo | Herbicide](https://gardensuperstore.com.au/weedmaster-duo-herbicide/) — Nufarm - [Glyphosate 360 | Herbicide](https://gardensuperstore.com.au/glyphosate-360-herbicide/) — PCT SureFire - [Weedpro 540 | Bio Herbicide](https://gardensuperstore.com.au/weedpro-540-bio-herbicide/) — PCT SureFire - [Crucial | Herbicide](https://gardensuperstore.com.au/crucial-herbicide/) — Nufarm - [Weedmaster DST | Herbicide](https://gardensuperstore.com.au/weedmaster-dst-herbicide/) — Nufarm - [Weedpro BioAqua 360 | Herbicide](https://gardensuperstore.com.au/weedpro-bioaqua-360-herbicide/) — PCT SureFire - [Arsenal Super | Herbicide](https://gardensuperstore.com.au/arsenal-super-herbicide/) — BASF - [Concentrate Advance Roundup Weedkiller](https://gardensuperstore.com.au/concentrate-advance-roundup-weedkiller/) — Roundup ## Image credits - [Photo: Arria Belli via Wikimedia Commons (CC BY-SA 2.0)](https://commons.wikimedia.org/wiki/File:Cyperus_rotundus_-_Kourou.jpg) - [Photo: Jeevan Jose, Kerala, India via Wikimedia Commons (CC BY-SA 4.0)](https://commons.wikimedia.org/wiki/File:Cyperus_rotundus_by_kadavoor.JPG) - [Photo: Jeevan Jose, Kerala, India via Wikimedia Commons (CC BY-SA 4.0)](https://commons.wikimedia.org/wiki/File:Cyperus_rotundus_at_Kadavoor.jpg) - [Photo: Javier martin via Wikimedia Commons (Public domain)](https://commons.wikimedia.org/wiki/File:Cyperus_rotundus_Enfoque_2010-7-11_LagunadelaMata.jpg)