|Production threat||Environmental threat||Public threat|
Darwin’s barberry is a woody evergreen shrub that grows to between 4-5m tall.
Darwin’s barberry (named after the naturalist, Charles Darwin) is very invasive in forests, riparian areas and in degraded pasture. It is considered a threat to forestry and native species and ecosystems. In the Waikato it is poised to become a serious forestry pest, as without control it will move into farmland and areas of indigenous forest.
Darwin’s barberry grows in scrubland, forests, plantation margins and road sides. Darwin’s barberry tolerates moderate to cold temperatures, damp to dry conditions, high wind, salt, shade, damage, grazing (not browsed), and a range of soils. It occasionally spreads by soil and water movement. It fruits earlier in the summer than many other species (both native and exotic) and its large amounts of seeds are dispersed widely by birds and other vertebrates such as possums. It can also regenerate via root suckers and layering.
Dense infestations near the Waikato region include Rainbow Mountain near Rotorua, within exotic forest in the Bay of Plenty region and the entire Kaingaroa Forest. There are also significant patches in the Manawatu-Whanganui region, southwest of Pureora Forest.
European barberry (B. vulgaris) is deciduous and has red berries. B. souliena and B. wilsonae are both cultivated. Barberry (B. glaucocarpa) has paler yellow flowers and less glossy leaves.
All landowners/occupiers in the Waikato are responsible for controlling Darwin’s barberry on their properties and are required to work with Waikato Regional Council in areas where control programmes are in place. Darwin’s barberry is also banned from being sold, propagated, distributed or included in commercial displays.
Smaller plants can be grubbed out. Leave on site to rot down (all year round). Cut stumps resprout quickly and can be hard to kill and seeds will germinate onto bare land. Follow up six monthly.
Apply with a low pressure sprayer using solid cone nozzle or a paintbrush. Liberally treat the full circumference and the basal parts of the shrub or tree trunks in a manner that thoroughly wets at least 2 to 3 times the diameter of the lower stem or trunk including the root collar area.
Cut the plant down, leaving a stump no higher than 5cm above ground level. Paint herbicide immediately over the entire stump surface, including the sides.
Make shallow downward cuts around the trunk and near the ground using a machete or axe. Cuts should overlap to effectively ringbark the tree. Apply herbicide immediately to the point of runoff into each cut.
Most suitable for smaller plants, but pulling out plants by hand may be cheaper and easier. Total coverage of leaf surfaces is required for effective control.
Disclaimer: Any product names mentioned below are not an endorsement nor are they a criticism of similar products not mentioned.
|X-Tree Basal®||Basal treatment of trunk (all year round).|
|Glyphosate or metsulfuron or picloram gel or triclopyr/picloram mix or triclopyr||Stump swab (all year round), frilling.|
|Metsulfuron||Cut and inject (all year round), frilling.|
|Metsulfuron or triclopyr/picloram mix||Spray (spring to autumn).|
|Herbicide rules will apply. You may need to notify neighbours if spraying. The Waikato Regional Plan explains the agrichemical (herbicides) use rule in section 6.2|
After initial control, it’s important to:
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