 |
| African Boxthorn (Lycium ferocissimum Miers) Control GuideRevised 11/02
African boxthorn is a native of South Africa and was most likely introduced into Tasmania around 1840 as a hedge plant. It is a member of the Solanaceae plant family, along with tomatoes and potatoes. It is reported as a troublesome weed only in Australia and New Zealand.
The plant is a woody shrub reaching up to 4.0m in height and can grow on a wide range of soil types. It forms an extensive root system incorporating a long branched taproot.
The trunk and branches are light brown and smooth when young, turning darker brown or grey and becoming rough with age. Main stems divide into many smaller branches, all of which end in a hard, sharp spike reaching up to 150mm long.
Foliage consists of glossy leaves up to 35mm long and 20mm wide. They are rounded at the top and taper to the base, and are usually arranged in small clusters at the nodes.
The flowers occur on slender stalks from the base of leaf clusters. The main flowering period is over summer, however flowering and seed production can occur through most of the year. The flowers are approximately 12 mm in diameter with five waxy white petals, each with a purplish base.
The fruit is an oblong berry approximately 10mm long. It ripens from a smooth green appearance to bright orange-red. It contains numerous small, oval, flattened seeds. Reproduction is mainly from seed. Birds eat the mature berries and distribute the seed far from the parent plant. Seed dispersal is also possible through the transport of mud or soil on machinery. Seeds germinate at any time of the year and generally take two years to reach flowering stage.
African boxthorn also has the ability to grow from root segments. Care must therefore be taken during manual removal to remove all sections of the root system.
African boxthorn is found in all States and Territories of Australia and is considered to be one of the country's most widespread weeds. In the mid 1800s it was widely propagated and sold by nurseries, however its weed impacts became apparent in the early 1900s and it was soon declared a noxious weed in many areas.
In Tasmania it is found throughout most agricultural areas of the State, including King Island and Cape Barren Island. It is commonly found along fencelines and beneath overhead wires as the seed is released by birds perching on the wires. It is also common along roadsides, railways and waterways.
The plant invades pastures and waste areas, reducing access and causing difficulty in stock movement. The spines are particularly hard and can easily injure people, animals and pneumatic tyres.
The sharp spines also protect the plant from grazing animals. This allows it to grow unchecked over large areas and form impenetrable dense thickets.
In a well managed situation, African boxthorn can form a very useful windbreak and hedge. Unfortunately it is difficult to restrict its flowering and seed production, as hard pruning into old wood doesn’t reduce the plant’s ability to produce flowers and fruits.
African boxthorn is a declared weed in Tasmania due to its impacts on agricultural productivity and the natural environment. As such, its importation, sale and distribution are prohibited. The legal responsibilities of landholders and other stakeholders for this declared weed are specified in a statutory weed management plan available from the Department.
Physical removal using heavy machinery is effective on large plants. The removed material should be destroyed, otherwise dead plants may provide shelter for vermin and the spines can still cause injury.
Small plants can be dug up and destroyed.
Once plants have been removed, the area will need to be monitored for regrowth from root sections left behind, or germinating seedlings. These can be easily pulled out if done early enough.
Soil cultivation can break up the old root systems and bring pieces to the surface to dry out. Establishment of vigorous pasture or a crop after cultivation will provide competition to new African boxthorn plants and restrict the amount of available light, water, nutrients and space.
A variety of herbicides are available which offer chemical control over African boxthorn.
After application of any herbicide, African boxthorn often looses its leaves quickly and appears to have died. Quite often the plant survives this period and then produces new foliage. If left unchecked, the plant can regenerate quickly. If this occurs, follow up chemical applications will be required to completely kill the plant. These should be done when a significant amount of regrowth has occurred, allowing adequate uptake of the herbicide.
Foliar Application
The herbicides glyphosate, triclopyr and a triclopyr/picloram mixture can be used as an overall spray for African Boxthorn. With all herbicides, complete coverage of all parts of the plant is essential.
Care must be taken using these herbicides as non-target plants contacted by the spray may be harmed. Picloram in particular remains active in the soil for extended periods and may leach into groundwater. Herbicides containing this active ingredient should not be used in orchards or horticultural areas.
Basal Treatment
For plants with a basal diameter up to 50mm, a mixture of triclopyr and diesel distillate may be applied to the lower 300mm of stems. This is done by thickly painting the mixture right around the stem.
Cut Stump Treatment
For large plants, the bush may be cut off 150mm above ground level. The freshly-cut stump must then be painted immediately with a chemical mixture to prevent regrowth. Triclopyr and diesel, or glyphosate formulation 1:1 with water can be used effectively.
Spotgun Treatment
The herbicide hexazinone may be applied on the soil surface or injected into the soil underneath the bush. Hexazinone remains active in the soil for extended periods and may leach within the soil and cause damage to other plants with roots in the vicinity.
Great care should be taken with this herbicide and application technique. Additional technical advice should be sought from the Department.
| Some herbicides are toxic to bees.
As a general rule, avoid applying herbicides when and where bees are foraging.
Always read the label. |
Disclaimer:
These herbicide recommendations are made subject to the product being registered for that purpose under relevant legislation. It is the user’s responsibility to check that registration or an off-label permit cover the proposed use. Always read the herbicide label. If in doubt, check with the Registrar of Chemical Products, Department of Primary Industries and Water. Statewide Freecall 1300 368 550.
| Type of Application | Herbicide
(Active ingredient) | Commercial products (Content of active ingredient) | Rate of commercial product per L | Comments | | Foliar Spray | glyphosate
glyphosate-
trimesium
triclopyr
triclopyr + picloram | Roundup® (360g/L) Glyphosate 360® (360g/L)
Roundup Biactive® (360g/L)
Roundup Dry® (680g/Kg)
Touchdown® (480g/L)
Garlon 600® (600 g/L)
Grazon DS® (300 g/L + 100g/L) | 7-10 mL/L
“
“
5 g/L
10 mL/L
1.7 mL/L
5 mL/L | Use lower rate for small bushes. Apply as a thorough foliage spray. Do not spray during hot, dry summer periods.
Apply as a thorough foliage spray when bushes are in full leaf and actively growing.
Use on plants less than 2m tall. Apply when bushes are in full leaf and actively growing. | | Basal Bark | triclopyr + diesel | Garlon 600® (600 g/L) | 33 mL/L diesel distillate | For treatment of plants up to 5cm in basal diameter. Do not treat during winter. | | Cut Stump | glyphosate
triclopyr + diesel
triclopyr | Roundup 360® (360g/L)
Glyphosate 360® (360g/L)
Garlon 600® (600g/L)
Treekill® (50 g/L) | 1L/L of water
33 mL/L diesel distillate
170mL/L of water | Use when basal diameter is greater than 5 cm. Apply to the freshly-cut stump. | | Spotgun* | hexazinone
| Velpar L® (250g/L)
Velpar 20G® (200g/Kg) | 4mL spots of undiluted product.
4g per square metre. | One measure for each metre in height, spaced evenly underneath the bush. Apply in spring or autumn when soil is moist. |
* Seek additional technical advice from DPIW before employing this method.
Note
Addition of adjuvants to most herbicides alters their effectiveness. Carefully consult each product’s label for specific directions before adding any adjuvant.
| |
