Osage orange (Maclura pomifera)

Also known as: bois d’arc, bow wood

Osage orange is a spiny tree or shrub with bumpy orange-sized fruit. It outcompetes native plants and forms thickets that limit access for people and animals.

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How does this weed affect you?

Osage orange:

• outcompetes native plants especially along riparian areas in inland regions of NSW.
• forms dense thorny thickets that limit movement of people and animals  
• exudes a milky sap that can irritate skin and eyes.

What does it look like?

Osage orange is a deciduous shrub or tree up to 21 m tall. The main trunk is short and topped with arching branches that give the plants a low rounded crown of dense foliage if they are not crowded by other trees. Trees can live for over 100 years. A milky latex exudes from the cut fruit and sometimes from the leaves and stems.

Leaves are 

• dark green, smooth and waxy above
• paler green and sparsely hairy below
• oval shaped with a pointed tip
• usually 5–15 cm long and up to 6 cm wide
• on a stalk 1.5–3 cm long
• alternate along the stem or in clusters at the end of the stems 
• yellow and translucent in autumn before falling from the plant.

Flowers

Male and female flowers are on separate trees. 

Male flowers are:

• green and hairy
• clustered along stalks up to 4 cm long
• each only a few millimetres wide.

Female flowerheads

• are green and round with up to 300 yellow hairlike threads 
• about 2.5 cm in diameter.

Fruit are:

• round with a bumpy surface
• bright yellowish green when ripe
• 10–15 cm in diameter
• brown when cut and exposed to air
• contain 200–300 seeds but are seedless if no male plants are nearby
• contain sticky milky latex. 

Seeds are:

•  oval shaped
•  up to 13 mm long
•  initially cream coloured, but will turn brown with age and exposure to air.

Stems:

• have spines 1- 5 cm long (more common on branches in full sun)
• are green and hairy when young
• are light brown with orange dots (lenticels) when older.

The main trunk on older plants has deeply furrowed, dark orange-brown bark and thorny branches.

Roots are 

• deep, up to 8 m 
• spread out laterally especially wide in shallow soil.

Where is it found?

In NSW plants have been found in the Central West, Greater Sydney, Northern Tablelands, South East and Riverina regions.

Osage orange is native to central United states of America.

What type of environment does it grow in?

Osage orange grows in temperate climates and can tolerate areas with frequent winter frosts. Plants grow best in full sun and moist soils though they are drought tolerant. Osage orange tolerates a wide range of soil types, including sandy-loamy soils and heavier black soils. 

Plants are often found growing along waterways and disturbed sites such as degraded paddocks.

Maps and records

• Recorded presence of Osage orange during property inspections (Map: Biosecurity Information System - Weeds, 2017-2026)
  These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.
  
  

How does it spread?

By seed

Trees usually start producing fruit when they are 10 years old. Fruit may be seedless if no male trees are nearby. Seeds may be dormant, but being in water for two days overcomes dormancy. Seeds are spread by water and animals including livestock and birds that eat the fruit and spread the seeds in their droppings. In NSW cockatoos and cattle have been seen eating the fruit. 

By plant parts

Osage orange can grow from cuttings or grafts. People have used this method to plant hedges in some parts of NSW.

References

Burton, J.D. (no date) Maclura pomifera (Raf.) Schneid. Osage-orange. United States Department of Agriculture. Retrieved 16 July 2024 from: https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/maclura/pomifera.htm

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 16 July 2024 from: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=gn&name=Maclura

Smith, J. L., & Perino, J. V. (1981). Osage orange (Maclura pomifera): history and economic uses. Economic Botany, 35, 24-41.

Starr, F., Starr, K., & Loope, L. (2003). Maclura pomifera. Osage orange, Moraceae. 

VicFlora (2024). Flora of Victoria, Royal Botanic Gardens Victoria. Available online: https://vicflora.rbg.vic.gov.au (accessed on: 16 July 2024)

Wynia, R. 2011. Plant fact sheet for Osage orange (Maclura pomifera). USDA-Natural Resources Conservation Service, Manhattan Plant Materials Center. Manhattan, KS 66502

More information

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Control

Treat Osage orange before it starts producing fruit whenever possible.

Wear protective clothing to prevent injuries from the thorns and the milky sap.

Physical

Small individual plants may be dug out.

Cutting down the tree and digging out the roots by machinery can be effective. However cutting plants and moving soil can trigger mass germination. Many plants in NSW are in sensitive riparian areas and care needs to be taken not to cause disturbance or erosion.

Chemical Control

Spraying

This method is effective for actively growing plants up to 2 m tall. It is best to treat plants that have full leaf growth during spring and summer. Cover all of the foliage with the herbicide mix.

Basal barking

Basal barking can be used on plants with stems up to 15 cm diameter at the base. Spray the bark all the way around the stem from ground level up to 30 cm high. Wet thoroughly to the point of runoff. Basal barking is effective, however it can be difficult to apply under some circumstances including:

• on multi-stemmed plants where not all the stems can be sprayed all the way around
• when flood debris has built up around the base of the stems
• when the trees are close to waterways.

Cut and paint

Cut stems less than 15 cm above ground level if possible. Apply the herbicide mix within 15 seconds by spraying the cut surface and sides of the stem.

 

Herbicide options

See Using herbicides for more information.

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Picloram 100 g/L + Triclopyr 300 g/L + Aminopyralid 8 g/L (Grazon® Extra)
Rate: 500 mL per 100 L of water
Comments: Spray actively growing plants. Follow the directions on the label for sweet briar.
Withholding period: Where product is used to control woody weeds in pastures there is a restriction of 12 weeks for use of treated pastures for making hay and silage; using hay or other plant material for compost, mulch or mushroom substrate; or using animal waste from animals grazing on treated pastures for compost, mulching, or spreading on pasture/crops.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Triclopyr 240 g/L + Picloram 120 g/L (Access™ )
Rate: 1 L in 60 L of diesel
Comments: Basal bark application for plants with stems up to 15 cm diameter at the base. Cut stump application for any sized stem: apply herbicide immediately after the cut. Follow the label instructions as per chinee apple
Withholding period: Nil
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Triclopyr 300 g/L + Picloram 100 g/L (Various products)
Rate: 500 mL per 100 L of water
Comments: Spray actively growing plants. Follow the directions on the label for sweet briar.
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Biosecurity duty

The content provided here is for information purposes only and is taken from the NSW Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area	Duty
All of NSW	General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.
Northern Tablelands An exclusion zone is established for all land in the region, except the core infestation, which includes the riparian area of the Macintyre River and its tributaries in the Inverell Shire.	Regional Recommended Measure* (for Regional Priority - Containment) Whole of region: Land managers mitigate the risk of new weeds being introduced to their land. Within exclusion zone: Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found. Within core infestation: Land managers should mitigate spread of the plant from their land. A person should not buy, sell, move, carry or release the plant into the environment. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
	*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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Reviewed 2025