Woolly nightshade

Woolly nightshade a rapidly growing shrub or tree. In large numbers it can rapidly invade poorly managed land and forest margins, totally excluding the regeneration of native plants. Dense stands can invade pasture on poor soils, especially in hill country, and impede livestock movement.

Fine hairs on its leaves and stems, that are shed when brushed or touched, can also be an irritant to some people and cause respiratory problems. The berries of woolly nightshade are moderately toxic to people (especially children), and they may be poisonous to livestock.

A single woolly nightshade plant can produce many thousands of seeds, which are spread by birds. These seeds can lie dormant in the soil and germinate up to 20-30 years later.

Woolly nightshade is now well established in many areas of the Waikato region north of Taupō (it is relatively frost intolerant). Within the Taupō and Rotorua districts, woolly nightshade has a limited distribution, however, where it occurs it may have significant impacts. For this reason, Waikato Regional Council will undertake control of woolly nightshade on all private, rateable land within the Taupō and Rotorua districts in the Waikato region. Outside these parts of the region, where woolly nightshade may be more widespread, occupiers are responsible for its control within 50m of any shared boundary where the adjacent or nearby occupiers are undertaking control of it.

Taupō and Rotorua district (within the Waikato region):

Waikato Regional Council is responsible for controlling woolly nightshade in the Taupō and Rotorua districts (within the Waikato region) and it is illegal for anyone else to remove or disturb it there. If you see woolly nightshade on your property in this part of the region, do not cut, treat or try to remove it. Call 0800 800 401 to report it to your local biosecurity pest plant officer.

Landowners/occupiers in the Waikato outside Taupō and Rotorua districts may control woolly nightshade as follows. 

Physical control

Small plants (less than 60cm) can be pulled out and left to dry after shaking all dirt from the roots. Larger plants that are cut down need to have the stump treated with herbicide or they will regrow. Try not to disturb the soil.

Herbicide control

Cut stump treatment

Cut the tree down, leaving a stump no higher than 5cm above ground level. Immediately (within two minutes of cutting) paint herbicide over the entire stump surface, including the sides.

Drill and inject

Drill 10mm holes around the trunk at a 45 degree angle, 50mm deep and 50mm apart. Fill each hole with herbicide.

Stem frilling

To control larger trees, make shallow downward cuts around the trunk below the lowest branch and near the ground using a machete or axe. Cuts should overlap to effectively ringbark the tree. Apply herbicide liberally to each cut.

Basal treatment of trunk

Using a specific basal treatment herbicide* liberally paint or spray the trunk from the ground to a height of 30cm to 50cm, making sure to cover the entire trunk. *Talk to your local herbicide retailer for more information.

Spray application

Totally cover the leaf surfaces with herbicide. This method is most suitable for smaller plants, but pulling out plants by hand may be cheaper and easier.

Safety when using herbicides

• Follow the instructions on the manufacturer’s label.
• Always wear protective clothing.
• Always minimise the risk to your other plants.
• Contact the supplier for further advice.

Summary of herbicides and application methods for control