What does it look like?
Perennial nettle has slender, rigid stems that are slightly branched at the top. The stems are square and covered in many stinging hairs. The leaves grow in opposite pairs and are heart shaped with sharply toothed edges. They are 7.5-15 cm long and are also covered in stinging hairs.
Male and female flowers occur on the same plant and grow in clusters from the leaf joints. The seeds are small (1–1.5 mm long), flattened and oval in shape.
Perennial nettle prefers damp, nutrient‑rich soils and is commonly found on farmland, along fence lines, in thickets, stockyards, waste areas and roadsides. Its seeds are spread by birds, and the plant also spreads vegetatively through stolons and rhizomes.
Why is it a problem?
Perennial nettle forms dense stands up to 1.5 metres tall, outcompeting native plants. Its stinging leaves can cause pain and swelling. The plant spreads through both seed and underground rhizomes, which can extend up to 2.5 metres in a single season. Perennial nettle is also a threat to pastoral land, as it displaces productive pasture species.
Control methods
Physical control
Digging out with regular and persistent tilling (deep cultivation or turning over of the soil) will greatly reduce plant numbers. Smaller plants can be hand pulled - gloves must be worn. Mowing the flowering plants is an effective way to reduce seed set but can increase plant density.
Herbicide control
Tordon Brushkiller is effective on perennial nettle, and Agpest note that nettle is very susceptible to MCPA and 2,4-DB which can be used in pasture with little effect on clovers.
Contact GWRC if you need further control advice.
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.
Management Programme
Unwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
More information
