Honey locust (Gleditsia triacanthos)

Honey locust (Gleditsia triacanthos) is a native of eastern and central North America. It was originally introduced into Australia as a garden plant and later, on a larger scale, for its value as a source of stock fodder.

NWW7309WX-Honey-locust-orchard-near-Bingara-NSW

NWW7309WX-Honey-locust-orchard-near-Bingara-NSW

The photo, right, shows an example of an “orchard” of honey locust trees (planted many years ago) grown for their value as a stock feed supplement (their seed pods) – this time in a paddock near Bingara, NSW. Take particular notice of the number of seed pods on each tree! Incidentally, all of these trees have since been removed.

Photo (below left) shows Clem McLeod (former Inverell Shire weeds officer) amongst large honey locust trees at Wells Crossing near Ashford, NSW – circa 2002 – trees since treated by Ashford Landcare Group

NWW7307WX-Honey-locust-Wells-Crossing-Ashford-with-Clem-McLeod-Oct-2000

Honey locust is now regarded as a serious pest plant along many of our river systems. It grows quickly, the thorns are a hazard to humans and animals, and infestations can become so thick they eventually cut off stock access to waterways.

Honey locust’s efficient means of spread, firstly through deliberate plantings in new areas, and subsequently through seed distribution via seed pods (photo below right #3) that cleverly float on water, has meant establishment in many parts of eastern Australia. Honey locust is now widespread along a number of inland river systems, including the McIntyre and Severn Rivers in Inverell Shire.

Honey locust grows to a height of 20 metres or more. The trees are armed with long and very tough spines, forming a formidable barrier to animals and humans as the trees become larger and more densely populated along watercourses etc. The seed pods grow to a length of up to 20 cm, each containing 20 to 30 seeds.

NWW73010WX-honey-locust-Coalmine-Rd-property-Severn-River-frontage

NWW73010WX-honey-locust-seed pods

To quote directly from the www.environment.gov.au website: “Honey Locust is an aggressive exotic tree. Although beneficial in the short-term as stock feed, the long-term consequences of its growth and spread are counter-productive. Honey Locust is an invasive tree capable of out-competing and replacing native vegetation. It can often create dense monocultures and hence provide restricted habitat for native fauna. The sharp barbs on its branches can also injure wildlife. These monocultures can also provide a haven for introduced pest animals such as foxes, cats and rabbits (Land Protection 2006)..”

CONTROL METHODS

Non-Chemical Options: Mechanical control is possible, but difficult. Heavy equipment may accelerate bank erosion. Would require follow-up treatments.

Chemical Options: According to NSW DPI’s excellent booklet “Noxious and Environmental Weed Control Handbook 5th Edition”, treatments include:

Chemical options Rate: Spot/Boom Comments
Triclopyr + Picloram Access ® 1.0 L in 60 L of diesel Basal bark application for basal diameter less than 5 cm or cut stump application for above 5 cm.
Fluroxypyr 333 g/LStarane Advanced® 300 mL per 100L of water Foliar application, seedlings & young plants up to 2 m in height.
900 mL per 100 L of diesel1.8 L per 100 L of diesel 3.0 L per 100 L of diesel Basal bark applicationPlants up to 10 cm basal diameter.Plants 10–20 cm basal diameter.Plants above 20 cm basal diameter.
3.0 L per 100 L of diesel Cut stump application.
Fluroxypyr 200 g/LVarious trade names e.g. Starane 200® 500 mL per 100L of water Foliar application, seedlings & young plants up to 2 m in height.
1.5 L per 100 L of water3.0 L per 100 L of water5.0 L per 100 L of water Basal bark applicationPlants up to 10 cm basal diameter.Plants 10–20 cm basal diameter.Plants above 20 cm basal diameter.
5.0 L per 100 L of diesel Cut stump application.
Picloram 45 g/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).

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. Updated – Les Tanner 22/07/2015