Weed Identification and Control


Redroot Amaranthus

Redroot Amaranthus

Technical Name: Amaranthus sp. General: Summer annual dying off with frosts in late autumn. Can be a major problem in crops as it’s quick growth and high germination rate can cause competition for resources in many crop species. Identification: Tall upright plant. Foliage is usually green but often has a reddish tinge. Stems can be […]

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Scotch Thistle

Scotch Thistle

Technical Name: Cirsium vulgare General: A biennial weed species. As the rosette grows close to the ground and its capacity to regrow if damaged it can tolerate mowing. As livestock don’t like eating the thistles it flowers freely in pastures. Seeds germinate when competition is low often in areas of bare soil from tracking damage […]

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Shepherd’s Purse

Shepherd's Purse

Technical Name: Capsella bursa-pastoris General: Small annual weed which can germinate at most times of the year. Commonly found in crops and gardens throughout New Zealand. It is often found in winter because of its ability to grow throughout the year and is more competitive when vigorous summer annuals are absent. Identification: Grows as a […]

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Annual Poa

Annual Poa

Technical Name: Poa annua General: Annual Poa is an infectious and widespread weed that thrives in temperate conditions. While Annual Poa can be controlled with cultivation, the species will continue to grow as a result of seed production. Identification: Annual Poa often flowers in winter, but can flower at any time of the year. The […]

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Yellow Bristle Grass

Yellow Bristle Grass

General: Yellow bristle grass occurs in areas with adequate summer rainfall, usually where the annual rainfall exceeds 500 mm per annum although it can tolerate dry conditions once established. It grows in areas where the soil has been disturbed, including cultivated areas, old pastures and along footpaths and the side of roads, especially where water […]

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Nettle

Nettle

Technical Name: Urtica sp. General: Often found in areas of tracking damage as seedlings struggle to compete around other plants. Unpalatable to animals. Identification: Upright plant that grow to 50cm. Has a distinctive jagged leaf-shape. Has long stinging hairs which give it its common name of ‘stinging nettle’.

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Kikuyu

Kikuyu

Technical Name: Pennisetum clandestinum General: Grass species with a low nutritional quality. Cannot tolerate frost. Can rapidly outcompete established pasture species. Identification: A tall annual grass with long silky stems. spreads rapidly through rhizomes and stolons forming a dense sward.  

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Mallow

Mallow

Technical Name: Malva sp. General: Unpalatable to animals. Grows mainly in pasture with areas of bare soil for tracking damage. Identification: 4 different species that can grow from prostrate to 1m. Distinctive geranium like leaves.  

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Nodding Thistle

Nodding Thistle

Technical Name: Carduus nutans General: Annual/ biennial weed species. Plants need a cold period before they become reproductive. This means autumn germinated seed will flower in the first summer (annual) and spring germinated plants will flower the next summer (biennial). Appear mostly in areas of tracking damage and areas of low pasture competition. Identification: The […]

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Paspalum

Paspalum

Technical Name: Paspalum dilatatum General: A rhizomatous grass. This weed is mainly a problem in turf in warmer climates. Can be a problem in pastures as the grass blades grow prostrate which make it difficult for animals to graze. Identification: Leaves grow prostrate and also has a purple tinge. It has a distinct seed head […]

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Pennyroyal

Pennyroyal

Technical Name: Mentha pulegium General: Pennyroyal affects mainly areas of poor soil drainage in pasture and turf. Has a strong minty smell when foliage is crushed. Warning: dairy cows that graze this weed can lead to milk tainting. Identification: Creeps along the ground by means of its stolon system to form dense mats of vegetation. […]

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Portulaca (Wild)

Portulaca (Wild)

Technical Name: Portulaca oleracea General: Grows mainly in pasture with areas of bare soil for tracking damage. Struggle to compete around other upright plants. Identification: An annual with fleshy prostrate red stems. The leaves are fleshy and short stalked. The flowers are stalkless and bright yellow.

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Spurrey

Spurrey

Technical Name: Spergula arvensis General: An annual weed species. Mainly establishing in autumn and flowering in spring. Can grow in dense clumps causing competition with crop and pasture seedlings. Seeds can remain dormant in soil for many years. Grow well under acidic soil conditions. Identification: Has sprawling stems and leaves are very narrow structures which […]

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Thorn Apple

Thorn Apple

Technical Name: Datura stramonium General: Strong-smelling annual. Found mostly in areas of bare soil from tracking damage or establishing pasture/ crops. Warning: plant is toxic to livestock. Identification: Erect spindly weed with alternate leaves coarsely-lobed or sharp-toothed. Has a characteristic white trumpet shape flower. Grows 1m.

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Fathen

Fathen

Technical Name: Chenopodium album General: Common summer annual weed species in pasture. Completely dies off during winter period. It is generally sensitive to most herbicides and so is relatively easy to control. Identification: Can grow to 2m. Has unique sword shaped leaves Flowering parts are similar in colour to the foliage. Flowers December and May

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Fleabane (Broad-Leaved)

Fleabane (Broad-Leaved)

Technical Name: Conyza sp. General: This common annual weed species are usually found in disturbed areas of pastures. These are normally irrigation ditches areas of that have lost pasture due to heavy traffic or cultivated soil. Some species have built a tolerance to glyphosate. Identification: A erect leafy weed. The stems are bristly and have […]

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Blackberry

Blackberry

Technical Name: Rubus fruticosus General: Blackberry can be found in swamp and wasteland areas hedges roadsides scrub and relapsing land. It has a perennial root system and a two-year growth pattern. Daughter plants are formed when the stems come in contact with the ground. Birds feed on blackberries but can also be dispersed through other […]

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Fumitory

Fumitory

Technical Name: Fumaria sp. General: An annual prostrate weed species. Can grow at any time during the year. it tends to not be competitive with other weed species. Identification: Has blue/green slender stems. Grows across the ground or by climbing other plants. The leaves are finely divided. They have unique purple flowers with black/red tips.

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Buttercup (Creeping)

Buttercup (Creeping)

Technical Name: Ranunculus repens General: Creeping Buttercup is the only buttercup species found in New Zealand that has a stolon system. This allows the creeping buttercup to spread sideways at a fast rate. Creeping Buttercup is suited to wet soil and poorly drained areas. Cattle and horses will avoid the weed. Identification: Made of three […]

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