There is a wide range of pest plants in Otago, a lot of them are escapees that were brought in to New Zealand for people’s gardens but jumped the fence and spread across our landscapes causing trouble for our native biodiversity.
Not all garden escapees are included in our pest plan for various reasons but that doesn’t mean they’re not weedy. Weedbusters has a lot of information or various pest plants and if you’re having trouble identifying a plant, iNaturalist is tool that allows you to add observations and have experts identify it for you.
Read our Pest versus Weed factsheet to see how we decide what is a pest plant under our Regional Pest Management Plan.
African feather grass
A tussocky grass that forms thick clumps up to 2m high. Report this pest!
African love grass
Grows as clumps of grass up to 1.5m tall with small white flowers and black-olive/purple seeds. Report this pest!
Banana passionfruit
A fast-growing vine with pink flowers and yellow fruit, that smothers other plants and harms native bush.
Bomarea
Bomarea is a climbing, woody vine with long, narrow leaves and large clusters of tubular flowers, typically orange, red, or yellow. Management programme: Progressive Containment.
Boneseed
Boneseed is a woody shrub with dull green leaves and bright yellow flowers. It spreads fast, forms dense patches, and pushes out native plants in coastal areas. Report this pest!
Broom
Broom is a woody shrub up to 3 m tall with small, hairy leaves in groups of three and bright yellow flowers (spring–summer). It spreads similarly to gorse, with explosive seed pods and durable seeds lasting 40–80 years.
Bur daisy
Bur daisy is a small, weedy herb with bright yellow pom-pom flowers that turn into hard, spiky burs. It spreads easily by sticking to stock and can quickly take over pasture, affecting wool quality and native plants.
Cape ivy
Cape ivy is a tangled, climbing plant that forms thick mats up to 2–3 m tall. Its leathery, pointed leaves and clusters of yellow ragwort-like flowers smother low-growing plants, preventing native seedlings from growing. It produces many long-lived seeds and is found mainly around Dunedin City and the Otago Peninsula in about 85 known sites.
Chilean flame creeper
A climbing vine with red tubular flowers, fast-growing and smothers native plants and trees.
Chilean needle grass
Chilean needle grass is a tough, tufted grass that grows up to 1 m tall. It forms dense patches and spreads sharp, barbed seeds that stick to animals, clothing, and vehicles. The seeds can cause painful injuries and even blindness in livestock. Report this pest!
Darwin's barberry
A spiny, evergreen shrub growing up to 4 meters tall, featuring glossy dark green leaves, clusters of deep orange-yellow flowers, and purplish-black berries.
False tamarisk
False tamarisk is a shrub up to 1.5 m tall with upright branches and small, bluish-green, narrowly triangular leaves. In summer (January–March), it produces small pink flowers in hanging clusters, followed by grey seed capsules. Report this pest!
Giant Hogweed
Giant hogweed is a very tall toxic plant with white flowers and purple-spotted stems. Its sap can cause burns, blisters, and even blindness. Report this pest!
Gorse
Gorse is a sharp, spiny shrub up to 4 m tall with bright yellow flowers from May to November. It spreads by explosive pods, water, and contaminated equipment. Gorse thrives across many habitats in Otago and forms dense, invasive patches.
Great willowherb
Great willowherb is a tall, pink-flowering plant that grows up to 2 m in damp places like wetlands, riverbanks, and ditches. It forms thick stands that squeeze out native plants, change water flow, and spread by seed, wind, water, machinery, shoes—and even underground roots. Report this pest!
Gunnera
Gunnera (also known as Chilean rhubarb) is a large, clump-forming plant that grows up to 2 m tall, with big leaves and strong red prickles on its stalks. It shades out other plants and forms thick stands along wet cliffs, riverbanks, and bluffs.
Japanese knotweed
Japanese knotweed is a fast-spreading weed, that can grow from pieces of root or stem. It quickly takes over an area, pushing out native plants and even damaging things like roads, walls, and buildings. Report this pest!
Moth plant
Moth plant is a fast-growing climbing vine that can reach over 5 m tall. It smothers shrubs, small trees, and native seedlings, harming biodiversity. Crush its stems or fruits and it oozes a caustic milky sap that can irritate skin and is poisonous to people. Report this pest!
Nassella tussock
Nassella tussock is a perennial grass that grows up to 1.5 meters tall, with long, fine leaves and distinctive fluffy seed heads. Management programme: Progressive containment,
Nodding thistle (pest)
Nodding thistle is a tall, spiny plant with large crimson flowers that droop when mature. Stock avoid it, and its dense rosettes reduce pasture for grazing. One plant can produce up to 10,000 seeds that stay viable for 20 years.
Old man's beard
Old man’s beard is a fast-growing climbing vine that smothers trees and native plants. It can reach up to 20 m high, has creamy-white flowers and fluffy seed heads, and spreads rapidly with about 1,000 seeds per m² that are wind-, water-, and bird-dispersed. Its stems also root easily, forming new plants.
Perennial nettle
Perennial nettle is a tall, stinging plant that can form thick stands in paddocks, riverbanks, and roadsides. Its sting irritates skin and deters animals, reducing usable grazing land. It spreads fast through underground rhizomes and thrives in both wet and dry areas.
Purple loosestrife
Purple loosestrife is a tall wetland weed with purple flower spikes that outcompetes natives, and blocks waterways. A single plant can produce up to 2.5 million seeds a year, spread by wind, water, and machinery. Report this pest!
Ragwort
Ragwort is a toxic yellow-flowering weed that harms livestock and reduces pasture.
Spartina
Spartina is an invasive estuary grass that forms thick clumps, traps sediment, raises flood risk, and alters bird habitats.
Spiny broom
Spiny broom is a sharp, invasive shrub with yellow flowers and flat seed pods that quickly takes over farmland and native areas.
Sycamore
A fast-growing deciduous tree with broad leaves and winged seeds that spread easily.
Tradescantia
Tradescantia is a fast-spreading weed that smothers the ground and stops native plants from growing. It breaks easily and grows from small stem pieces, making it hard to get rid of.
White-edged nightshade
White‑edged nightshade is a spiny, fast-growing shrub with pale flowers and tomato-like berries that smothers farmland and native plants.
Wild Russell lupin
Wild Russell lupin forms dense clumps along braided rivers, altering water flow, smothering bird nesting sites, and increasing flood risks.
Wild ginger
Wild ginger forms dense clumps that smother native bush and stop new plants from growing. It spreads quickly and is hard to remove.
Wilding conifers
Wilding conifers are invasive pine and fir trees spreading into tussock and farmland, reducing grazing land and increasing fire risk.
Yellow Flag Iris
Yellow Flag Iris is poisonous to humans and animals. It grows up to 1.5 meters tall, with broad, flat, sword-shaped leaves, and bright yellow flowers.
