Quick Facts

Quick facts

• Honey Locust (Gleditsia triacanthos) was introduced from North America as a fodder tree and cultivated as an ornamental.
• It is an invasive tree capable of out-competing and replacing native vegetation and destroying pasture.
• It forms dense thickets along watercourses and the trunk is protected by thorns, preventing both human and stock access and providing shelter for feral animals.
• Honey Locust grows large spines on its trunk that grow up to 10 cm long.

What Does It Look Like?

What is it?

Honey Locust (Gleditsia triacanthos) is a deciduous, leguminous tree growing to 25 m tall. From spring to autumn it bears prolific green leaves (to 20 cm long), with about twelve pairs of opposite leaflets. The trunk and limbs of 'wild' trees usually bear very large, branched like spines that can grow more than 10 cm (Land Protection 2006).

In October to November it bears hanging clusters of creamy-yellow flowers (to 10 cm long) that develop into 20–30 cm long, slightly sickle-shaped, brown pods. Sepals and petals are similar, brownish-yellow, with 3–5 of each. Some varieties have separate male and female plants, while other varieties are bisexual.

The plant seeds prolifically every 1–2 years and the pods (fruit), filled with a sweet pulp around the seeds, are relished by stock.

For further information and assistance with identification of Honey Locust contact the herbarium in your state or territory.

Flower colour

Yellow

Growth form (weed type/habit)

Tree

Where it currently grows? Preferred habitat

Honey Locust can grow in most soil types but prefers alluvial flood plains along river systems. It is extremely drought tolerant. In the past, impenetrable thickets have smothered large areas of highly productive alluvial grazing land near Toogoolawah in Queensland (Land Protection 2006).

Are there similar species?

Honey Locust is unlikely to be confused with any other plant as its prominent, branched thorns are highly distinctive.

Why Is It A Weed?

What are its impacts?

Honey Locust was included in the list of 71 species that were nominated by state and territory governments for assessment as Weeds of National Significance (WONS). Following an assessment process, Honey Locust was not included as one of the 20 WONS. However, it remains a weed of potential national significance.

Agriculture: 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. If not controlled, Honey Locust can destroy pastures by smothering the more desirable grass species. The plant can form dense thickets, particularly along waterways, preventing stock access to water (Land Protection 2006).

Native ecosystems: 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).

Human impacts: The plant's long, strong spines can inflict serious injuries and infections to humans and livestock. They can also cause damage to vehicle tyres, restricting vehicle movement near infestations. Even when the plant has died, spines can continue to inflict injury (Land Protection 2006).

How does it spread?

Honey Locust spreads by seed and suckering. Seeds are spread in animal dung and by water as the pods float (Weeds Australia undated). It can also spread by people planting Honey Locust trees as an ornamental or for fodder (Land Protection 2006).

What is its history in Australia?

Honey Locust was introduced by William Macarthur to 'Camden Park', Camden, New South Wales in the mid 1800s, as a fodder tree and cultivated as an ornamental. In the past it has been deliberately promoted and planted in Australia as a fodder tree and garden ornamental. It was planted in Queensland as early as 1907 to provide cattle fodder and was first reported as a pest there in 1955 at Cressbrook Creek (Esk Shire). By 1992, substantial infestations existed over more than 1000 hectares in the Brisbane Valley and southern Darling Downs in Queensland (Weeds Australia undated; Csurhes 2004; Land Protection 2006).

How To Manage It?

Best practice management

A combination of different control methods is likely to be the most efficient approach. 

Chemical control: Physical control methods can be effective but will usually need to be followed up with chemical control.

Non-chemical control: Land management: Continual grazing suppresses seedlings but can also assist in spreading seeds into new areas. Grazing can be a useful follow-up control method after herbicide treatment to control seedlings and regrowth, providing the plants do not bear seed pods. For the control of dense infestations on grazing land, burning followed by spot spraying is an economical control method (Land Protection 2006).

Mechanical control: Bulldozers can be used to break a plant at or above ground level. Once broken, Honey Locust will vigorously produce regrowth from broken bases and roots. Follow-up with some other form of control such as cultivation or herbicide is necessary (Land Protection 2006). On arable land, dozing following by deep ploughing can control dense infestations, only if followed by regular cropping and/or spot spraying of regrowth. If cultivation is abandoned, reseeding from nearby trees can be a problem (Land Protection 2006).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au.

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Honey Locust seedlings take up to two years to set seed (Land Protection 2006).

In North America the minimum seed-bearing age of honey-locust is 10 years. Optimum seed production occurs from about 25 to 75 years of age. Seeds are produced until about age 100. Large crops usually occur every other year but can be produced annually. Some seed is usually produced every year. Honey-locust seed is viable for long periods due to an impermeable seedcoat. Honey-locust begins to flower when its leaves are nearly full grown, during early to late spring. The legumes ripen during autumn, usually falling after ripening but sometimes remaining on the tree through winter (Sullivan 1994).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, VIC

What areas within states and territories is it found?

Honey Locust is found along the central coast, western slopes and tablelands of northern New South Wales and in south eastern Queensland (e.g. Darlings Downs and Toogoolawah, where heavy infestations occur). It is not common in Victoria (where it occurs along the Murray River). Although present in South Australia and Western Australia it appears not to have naturalized (Weeds Australia undated; Land Protection 2006).

The Queensland Department of Natural Resources and Water initiated an eradication project in 1993. All major infestations had been treated by 2006 and it is now difficult to find an infestation in Queensland (Csurhes 2004; Land Protection 2006).

Honey Locust is an adaptable species and is presently free of insects and disease. Its potential for spread over large areas is enormous. There are no reasons, climatic or otherwise, why Honey Locust tree should not spread throughout south-east Queensland, especially on alluvial soils in the Brisbane Valley and Darling Downs (Land Protection 2006).

Collections of Honey Locust have been recorded in Western Australia but it is not recorded as naturalised in the state yet.

Where does it originate?

Honey Locust is native to eastern and central North America (Weeds Australia undated).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, QLD, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Gleditsia triacanthos

Other scientific names (synonyms)?

Does it have other known common name(s)?

McConnel's Curse, Bean Tree, Sweet Locust, Three-thorned Acacia