One of the reasons African boxthorn (Lycium ferocissimum) became so widely established since its introduction into Australia is because it was originally promoted and grown as a hedge plant.
A hardy plant, fast-growing, and covered in sharp thorns, African boxthorn made an effective boundary “fence” between properties in some areas in the early days of rural settlement. Its popularity as a garden plant is another reason why we continue to find boxthorn around towns and homesteads.
African boxthorn produces small, orange-red berries. Birds are very efficient at spreading the seeds over large areas..
Most seeds are dropped underneath trees by birds – the resultant seedling growth eventually becomes dense enough to take over the entire shaded area, denying shelter to livestock.
These thick patches provide a perfect harbour for feral animals including rabbits, foxes and pigs.
The problem with African boxthorn is its invasiveness. It takes over shaded areas first and keeps spreading. It can seriously reduce a property’s stock-carrying capacity. And, the plants’ sharp thorns have been known to damage the eyes of grazing animals, especially during dry times when the animals are chasing the last bits of grass.
IDENTIFICATION African boxthorn grows to a height of around 3-4m. The plant takes on a bright green colour during its main
growing period – May-September. Flowers are a creamy colour about 10mm in diameter. The ripe, red berries are about the size of “table peas”. The plant doesn’t usually start to produce fruit until two years old. Every limb is covered with sharp, strong spines growing to about 75mm long.
Mechanical removal and stacking of plants, using a tractor and blade, is an immediate way of cleaning up unsightly boxthorn infestations. (Note 1. plants are easier to remove i.e. more of the root system will come out if deep soil is moist and 2. always push the plants into heaps well away from desirable trees for subsequent burning – subject to fire restrictions of course). There will be seedlings and other regrowth from where the plants were – continue to remove or chemically treat new growth until plants eventually give up.
Chemical Options: There are a variety of herbicides available, but treatment should only be carried out when plants are actively growing. August/September are usually the best months in north west New South Wales – as long as the plants are NOT moisture-stressed (one test is that if leaves easily fall off when the plant is lightly tapped with a stick, it’s too late!). Pushing large plants out of the ground first with a blade, as mentioned above, will reduce herbicide usage but the areas will certainly need to be followed for regrowth and seedlings.
Glyphosate is the herbicide most used for boxthorn. It doesn’t pose a risk to the trees and if used at the right rate (NEVER STRONGER THAN THE LABEL RECOMMENDATION), and if the WHOLE PLANT is sprayed AT THE RIGHT TIME, glyphosate will do a good job. If the herbicide is too strong, the plant will shut down before the chemical works its way through the root system…
According to NSW DPI’s excellent booklet “Noxious and Environmental Weed Control Handbook 3rd Edition”, treatments for African boxthorn include:
|Chemical options||Rate: Spot/Boom||Comments|
|Triclopyr +Picloram eg Grazon DS®||500 ml in 100 L of water||Apply when bushes have good leaf cover, growth and no leaf fall|
|Triclopyr + Picloram Access ®||1.0 L in 60 L of diesel||Apply as basal bark/cut stump application|
|Picloram +2,4 -D eg Tordon 75D ®||1.3 L in 100 L of water||Small bushes only. Spray soil to drip line. Thorough coverage is essential|
|Glyphosate 360 g/L Various trade names||700 ml to 1.0 L in 100 L of water||Low rate on young bushes, high rate on mature bushes. Thorough coverage is essential. NOTE: Do not make the mix any stronger than the label recommendation! A slow kill is a good kill because the herbicide has more time to work its way right through the root system. 1.0 L of 360 g/L is equal to 800 mL of 450 g/L (eg Roundup CT) or 660 mL 540 g/L (eg PowerMax®)|
|Glyphosate 540 g/L e.g. Roundup PowerMax®||330-660 mL in 100 L of water||The PowerMax® label also carries the recommendation: Removal of bushes (after complete brownout), pasture improvement or further treatment is recommended to control seedlings and/or regrowth|
|Glyphosate – trimesium Touchdown®||1.0 L in 100 L of water||Actively growing bushes. Spray thoroughly|
|Triclopyr eg Garlon 600®||1.0L in 30 L of diesel||Cut stump /basal bark application|
|Tebuthiuron eg Graslan® pellets||2 g per square metre||Estimate the area within 30 cm beyond the drip line of the target plant – calculate the amount of Graslan required to cover the area and distribute evenly in this area. Do not use within 30 m of desirable trees|
|Hexazinone eg Velpar L®||4 ml per spot||Bushes up to 3m tall. 1 spot per metre of height. Do not apply near desirable trees|
|Picloram 45g/kg Vigilant®||Undiluted||Cut stump/stem injection application. Apply a 3–5 mm layer of gel for stems less than 20 mm. Apply 5 mm layer on stems above 20 mm (see label)|
MORE INFORMATION: Noxious Plants of Australia, by Parsons & Cuthbertson. Inkata Press.
IMPORTANT: USE OF PESTICIDES – ALWAYS READ THE LABEL Pesticides must only be used for the purpose for which they are registered and must not be used in any other situation or in any manner contrary to the directions on the label. Never use a herbicide in any way contrary to the label recommendations.
DISCLAIMER: The information contained in this web site is based on knowledge and understanding at the time of writing. However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of North West Weeds or the user’s independent adviser. Les Tanner 26/07/2015