A common name Allocasuarina nana is Stunted Sheoak but we feel that a more appropriate title should be Dwarf Sheoak. It is a small dense shrub that will reach a height up to 1.5 metres.
Allocasuarina nana occurs in New South Wales only; on the central and southern coast and tablelands areas, south from around Kandos, as far west as Lithgow and the Briadwood-area. (The specimen illustrated is growing in the Box Vale Reserve near Mittagong in the Southern Highlands of New South Wales. We have also observed the Dwarf Sheoak growing in the Blue Mountains of New South Wales and in Deua National Park in southern New South Wales. In this latter location, Allocasuarina nana grows on hillsides and is the dominant understorey shrub). It is not recognised as occurring in Victoria.
In Allocasuarina spp., the leaves are reduced to whorls of teeth around the brachlets (with the brachlets taking over the role of the “foliage”). The Dwarf Sheoak has 5 to 7 leaf-teeth in a whorl (a feature which aids identification of species in this genus). Each ‘leaf-tooth’ is very small, less than 1 mm long.
Allocasuarina spp. are flowering plants (not pine trees – a mistake made by some). Their closest relatives are plants such as birch trees and alders (not known for their showy flowers).
They are usually dioecious (male and female flowers on separate plants). The male flowers are carried in spikes on the ends of branches. The spikes are typically very narrow (2-3 mm across) and around 40 mm long, consisting of very small flowers. When the flowers mature, pollen is released and spread by the wind.
Female flowers are in globular heads on short stalks along branches and are usually arranged in leafy-clusters. These flowers are highly modified – lacking obvious petals and sepals. The globular heads consist mainly of female styles.
Pollinated female flowers develop into persistent, woody, globular “cones” – a cluster of woody valves (bracteoles) that function individually like follicles to release the seed. Each cone contains many small, winged seeds or samaras. In Allocasuarina spp., the seeds are usually black and shiny. The appearance of the fruit differs between species. In this species, the cone is 25 mm long by 15 mm wide, round and with a tessellated surface with the woody valves pointy.
Allocasuarina nana is an attractive small shrub that could be grown as a foreground plant in a native garden bed. The Dwarf Sheoak could also be used as a low, informal hedge in the larger garden. The species would make an excellent native substitute for the ubiquitous, slow-growing English Box in this situation.
It has fine dense foliage which makes a strong contrast. It likely requires a free-draining sandy soil to thrive.
It is known to be cultivated.
Propagate from seed and possibly cuttings.
The type material may have been collected in the Blue Mountains or possibly the Royal National Park, Sydney.
Allocasuarina spp. can regenerate from seed after fire. They can also exhibit suckering from root zones.
Allocasuarina is a genus of about 62 species – all endemic to Australia. There are currently 19 species recognised in NSW.
Allocasuarina – Greek – Allo – meaning “other” – referring to this genus and its species being considered different to Casuarina. This genus was only established in 1982, by L.A.S Johnson (1925-1997).
nana – Latin – meaning “dwarf” – referring to the small size of the species – much smaller than most other Allocasuarina spp.
This species is not known to be at risk of extinction in the wild.
NSW Flora Online (PlantNET) – Allocasuarina nana profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Allocasuarina~nana
Plants of South Eastern NSW – Allocasuarina nana profile page https://apps.lucidcentral.org/plants_se_nsw/text/entities/allocasuarina_nana.htm
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.