We have recently published ‘Food Forest Plants for Hotter Conditions’: i.e. tropical and sub-tropical regions. We rely on regular donations to keep our free database going and help fund development of this and another book we are planning on food forest plants for Mediterranean climates. Please give what you can to keep PFAF properly funded. More >>>

Follow Us:


Castanospermum australe - A.Cunn.&C.Fraser. ex Hook.

Common Name Moreton Bay Chestnut
Family Fabaceae or Leguminosae
USDA hardiness 8-12
Known Hazards The immature seed is poisonous, though mature seeds are harmless[167, 240]. Another report says that the raw seed is poisonous and needs treatment to render it edible[193].
Habitats Subtropical and tropical gallery-type rainforests and on the banks of creeks[ 144 , 303 ], usually in good rich moist soils[ 167 ].
Range Australia - New South Wales, Queensland.
Edibility Rating    (4 of 5)
Other Uses    (3 of 5)
Weed Potential No
Medicinal Rating    (1 of 5)
Care (info)
Half Hardy Moist Soil Full sun
Castanospermum australe Moreton Bay Chestnut

Castanospermum australe Moreton Bay Chestnut


Translate this page:


Other common names include Morten Bay Chestnut, Morton Bay Chestnut, Black Bean Chestnut. Moreto Bay Chestnut or Castanospermum austral is a tropical, evergreen tree of about 18-35 m tall and 5-12 m width with an erect trunk, grey to brown smooth bark, and glossy dark green leaves. The flowers are pea-shaped, yellow to orange in colour and form into clusters. The seed is edible when cooked but requires extensive leeching prior to consumption due to its high saponins content. Further, it contains castanospermine, a compound which may be useful as HIV inhibitors. C.australe has an extensive root system. The wood is durable, hard, and heavy and is used as material for construction, etc.

Physical Characteristics

 icon of manicon of cone
Castanospermum australe is an evergreen Tree growing to 25 m (82ft) by 20 m (65ft) at a slow rate.
See above for USDA hardiness. It is hardy to UK zone 9. It is in leaf all year, in flower from September to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Birds.
It can fix Nitrogen.
It is noted for attracting wildlife.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid and neutral soils and can grow in very acid soils.
It cannot grow in the shade. It prefers moist soil.

UK Hardiness Map US Hardiness Map


Plant Habitats

Woodland Garden Canopy; South Wall. By. West Wall. By.

Edible Uses

Edible Parts: Seed
Edible Uses:

Seed - cooked[ 1 , 46 , 61 , 105 ]. The fresh raw seed contains high levels of saponins[ 238 ] and can be harmful[ 34 , 63 ]. The cooked seed tastes like a sweet chestnut[ 2 ]. It probably requires considerable leeching before it is safe to eat[ 144 ]. The Australian aborigines finely sliced the seeds and soaked them in running water for 10 days before roasting them and grinding them into a powder[ 193 ]. This powder could be stored for later use[ 193 ]. The seeds are about 3 - 4.5cm wide and are carried in pods 10 - 25cm long and containing 3 - 5 seeds[ 193 , 260 ].

References   More on Edible Uses

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.
Astringent  Miscellany

The seed yields compounds called castanospermine that are under investigation as HIV inhibitors and might be useful in the treatment of AIDS[ 200 , 238 , 260 , 303 ]. The seedpods are astringent[ 240 ]. Used to treat post-prandial hyperglycaemia in diabetic patients[ 303 ].

References   More on Medicinal Uses

The Bookshop: Edible Plant Books

Our Latest books on Perennial Plants For Food Forests and Permaculture Gardens in paperback or digital formats.

Food Forest Plants for Hotter Conditions: 250+ Plants For Tropical Food Forests & Permaculture Gardens.
Edible Tropical Plants

Food Forest Plants for Hotter Conditions: 250+ Plants For Tropical Food Forests & Permaculture Gardens.

Plants for Your Food Forest: 500 Plants for Temperate Food Forests & Permaculture Gardens.
Edible Temperate Plants

Plants for Your Food Forest: 500 Plants for Temperate Food Forests & Permaculture Gardens.

PFAF have eight books available in paperback and digital media.
More Books

PFAF have eight books available in paperback and digital formats. Browse the shop for more information.

Shop Now

Other Uses

Miscellany  Wood

Other uses rating: Medium (3/5). Flowering tree, Public open spaces, Street tree, Specimen. Agroforestry Uses: The extensive root system is used to protect riverbanks and catchment areas in Australia[ 303 ]. Other Uses The seeds have a high saponin content[ 238 ]. Although the report does not elaborate, the saponins could probably be used as a soap substitute[ K ]. The seeds contain toxic saponins which are reportedly toxic to a serious pest of stored grain[ 303 ]. The wood can be used as a fuel[ 303 ]. Wood - durable, resists decay, hard, heavy, polishes well, has a high resistance to the passage of electric current. The sapwood varies from white to yellow. The heartwood is dark-brown to almost black, slightly greasy and straight grained but sometimes interlocked[ 303 ]. Used in construction, cabinet making, carving etc[ 61 , 144 , 156 , 167 ]. One of the most valuable woods in Australia, the sliced veneers can be good substitute for teak[ 303 ]. The wood has a density of 700 kg /cu m[ 303 ].

Special Uses

Carbon Farming  Nitrogen Fixer  Scented Plants

References   More on Other Uses

Cultivation details

Industrial Crop: Starch  Management: Standard  Regional Crop

A tree of moist, lowland tropical and subtropical climates, it grows best at an elevation between 50 - 750 metres[ 303 , 418 ]. It grows best in areas where annual daytime temperatures are within the range 20 - 32°c, but can tolerate 10 - 41°c[ 418 ]. It prefers a mean annual rainfall in the range 1,600 - 3,200mm, but tolerates 1,000 - 3,800mm[ 418 ]. Requires a very well-drained[ 260 ] but moist high-grade soil and a very sunny position when grown in areas cooler than its natural climate[ 167 , 200 ]. Prefers a pH in the range 5 - 6, tolerating 4.5 - 6.5[ 418 ]. The crushed leaves smell like cucumbers[ 193 ]. Flowers are produced on the old wood[ 260 ]. The flowers are rich in nectar and are pollinated by parrots in the wild[ 260 ]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[ 200 ].

Carbon Farming

  • Industrial Crop: Starch  Materials and chemicals include bioplastics, paper, cardboard, solvents, paints, glues etc. Plants are usually pods, starchy fruits, nuts & seeds, starchy trunks.
  • Management: Standard  Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.
  • Regional Crop  These crops have been domesticated and cultivated regionally but have not been adopted elsewhere and are typically not traded globally, Examples in this broad category include perennial cottons and many nuts and staple fruits.

References   Carbon Farming Information and Carbon Sequestration Information

Temperature Converter

Type a value in the Celsius field to convert the value to Fahrenheit:



The PFAF Bookshop

Plants For A Future have a number of books available in paperback and digital form. Book titles include Edible Plants, Edible Perennials, Edible Trees,Edible Shrubs, Woodland Gardening, and Temperate Food Forest Plants. Our new book is Food Forest Plants For Hotter Conditions (Tropical and Sub-Tropical).

Shop Now

Plant Propagation

Seed. Prick out the seedlings into individual deep pots as soon as they are large enough to handle and plant out when 15cm or more tall.

Other Names

If available other names are mentioned here

Other Names: Australian chestnut, Bean tree, Black bean.

Found In: Africa, Asia, Australia, Central America, East Africa, Fiji, Hawaii, India, Kenya, New Caledonia, Malaysia, Mozambique, Norfolk Island, Pacific, Pakistan, Papua New Guinea, PNG, SE Asia, Solomon Islands, Southern Africa, Sri Lanka, USA, Vanuatu, West Indies, Zimbabwe.

Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

None Known

Conservation Status

IUCN Red List of Threatened Plants Status : This taxon has not yet been assessed.

Related Plants
Latin NameCommon NameHabitHeightHardinessGrowthSoilShadeMoistureEdibleMedicinalOther

Growth: S = slow M = medium F = fast. Soil: L = light (sandy) M = medium H = heavy (clay). pH: A = acid N = neutral B = basic (alkaline). Shade: F = full shade S = semi-shade N = no shade. Moisture: D = dry M = Moist We = wet Wa = water.


Expert comment


A.Cunn.&C.Fraser. ex Hook.

Botanical References


Links / References

For a list of references used on this page please go here

Readers comment

cathy   Wed Sep 24 07:19:34 2003

I live in Melbourne, Australia - this tree is in my back yard - it flowers each year at Christmas. The flowers are a beautiful orange waxy tubular flower- very showy and very tropical. It survives our cold winters very well. We let the seed pods fall and every year several self propagate. I have always been wary about eating the chestnut like seeds as there are conflicting reports as to whether they are poisonous. It is a messy tree, leaves falling in spring and flowers in summer ( a carpet of orange) but well worth it. It has soft wood and is easy to prune. Ours is quite small - 5-6 metres great for kids to climb in because of its smooth bark.

Annette   Mon Aug 1 01:17:26 2005

The website below provides comprehensive information about this species. It is also an excellent site for finding information about other Australian species.

Link: Australian Government - Department of the Environment and Heritage

serega   Thu Dec 15 2005

À ó ìåíÿ íåòó è íàôèã íåíàäà

Daniela   Wed May 10 2006

This plant has some more medicinal uses: The alkaloid it contains inhibits the enzyme sucrase, and thereby blocks digestion of sugar. It has potential to treat diabetes and obesity.

Helene Bonavita   Fri Feb 15 2008

I live in Uruguay, South America, where there are some very few of these trees. But they are also selfpropagated in our region, since our climate is quite similar than the Australian climate. From 28 seeds I planted in individual pots last spring, 27 grew up to 30 cm in the summer after waiting aprox. 40 days to their germination. One of them has totally light yellow folliage, even the stems are yellow colored. I am watching specially over this one to see how it grows and if it maintains its very interesting pallette. It seems to prefer light shadow and can get burned leafs if left in full summer sun. I wonder if it can be a subspecies? Could noy find any information abuçout it on the web

tom   Thu Feb 21 2008

We have a nice one growing in a front yard in Orlando, Florida. IKEA sold them as saplings for use as houseplants; but, as most houseplants do very well outdoors in our climate, I gave it a try. It's made it through several light frosts without any damage and has reached a height of 2.5m. No flowers yet, though.

nikki   Thu Feb 28 2008

This information has helped me alot with my sinece assignment. It gave me nealy all the answers or help to get the answers.

lesa   Mon Apr 7 2008

how long do these take to grow?

G Mohr   Wed May 28 2008

I've been growing one in a pot for nearly 10 years. It's about 5'6" tall and seems healthy but it has never flowered or produced seeds. Is there anything I can do to get it to flower?

BILLY HENDRIX   Mon Feb 9 2009

I am researching the uses of these seed and I can not find any information about the possible oil extraction. It shows me that it might be possible to ferment for a possible source of material to use in the production of ethanol. What is your opinion? Thank you.

BILLY HENDRIX   Mon Feb 9 2009

Thank you for emailing back. Billy

BILLY HENDRIX   Tue Feb 10 2009

someone has sent me an email, that links me to this site, but I can not find any message. Where I am I to look???

Lachlan Scanlan   Tue Apr 21 2009

The ability these plants show for tolerating low light has given rise to their popularity as an indoor foliage plant. They are typically multi-planted ie many seeds direct sown into a pot for this purpose. As stated above they are easily germinated and it is commom to see many dozens to hundreds of juveniles germinating and growing beneath parent trees. Interestingly cattle are known to become addicted to these seeds which eventually result in a slow death(weeks)to the animal if not removed from the source of seed. Already sick cattle once yarded(locked away) from the trees crave the seeds so much they may jump fences to get back to them. This problem mainly on dairy farms led to widespread removal of the trees from dairy farms in particular.

AMBER   Tue Aug 11 2009

My friend recieved a planted seedling in a small pot (the plant is about 12- 16 inches tall now). We would like to know when to transplant, if the plant likes lots of room for its roots or to be slightly root bound. Thank you so much for the other information I have read in this site.

catherine   Tue Jan 12 2010

Please advise if these trees, we have 3 in pots, can be planted near swimming pools? Is there a problem with the roots? Thanks very much.

   Feb 25 2017 12:00AM

Mature seeds are also deadly poisonous and require preparation before eating. The traditional process includes...cooking the seeds for 3 hours or so, cutting up the seeds finely, leaching them in a stream for 3-7 days, crushing the pulp into think cakes (or biscuits) then baking them. If you miss one of those steps you're likely to make yourself very sick. These were a staple for Australian aboriginals so they do have great food value but only if they're prepared properly. There are probably modern methods of safe preparation that might work too. There's a video here of preparing and eating the seeds... https://www.youtube.com/watch?v=eVvQnsKuOcE

Add a comment

If you have important information about this plant that may help other users please add a comment or link below. Only comments or links that are felt to be directly relevant to a plant will be included. If you think a comment/link or information contained on this page is inaccurate or misleading we would welcome your feedback at [email protected]. If you have questions about a plant please use the Forum on this website as we do not have the resources to answer questions ourselves.

* Please note: the comments by website users are not necessarily those held by PFAF and may give misleading or inaccurate information.

To leave a comment please Register or login here All comments need to be approved so will not appear immediately.

Subject : Castanospermum australe  
© 2010, Plants For A Future. Plants For A Future is a charitable company limited by guarantee, registered in England and Wales. Charity No. 1057719, Company No. 3204567.