Sweet Bursaria, Native Blackthorn, Castanet Bush, Christmas Bush, Australian Blackthorn, Australian Boxthorn, Black Thorn, Blackthorn, Geapga, Kurwan, Mock Orange, Native Box, Native Olive, Prickly Box, Prickly Pine, Spiny Box.
Bursaria, from Latin bursa, a purse, referring to pouch-like capsules. Spinosa, from Latin spinosus, thorny, referring to thorny branches. Note that the botanical name is in the process of being changed to Bursaria spinosa subsp. spinosa.
Up to 8m.
Presence in Australia
Widespread. Sweet Bursaria occurs predominantly in the drier, western areas of the region.
This specie has been identified in the following Australian states: Qld, NSW, ACT, Vic, Tas, SA, WA.
Dry or wet sclerophyll forest, on non-siliceous soils.
Shrub or small tree to about 8m high with leaves green on both surfaces.
Distinguish Bursarias by the leaf underside. Sweet Bursaria leaves green on both surfaces. Hairy Bursaria has downy white leaf underside.
Well-drained soil. Tolerates frost and wind.
Long-lived. May be slow-growing.
White to cream - chiefly summer.
Late Jan to early May, when ripe fruit rattle. Timing depends on season and location of plants, with seed on plants east of the Hume Highway ripening later than seed on plants further west.
From seed (±190 viable seeds per gram), and cuttings. Stratifying seed by combining with moist sand and refrigerating for 6 weeks enhances germination. Sow around Jun-Jul when temperatures low and days short. Germination may take several months. Seedlings prone to late damping-off. Treat with fungicide to reduce losses.
From seed over winter. Seed dispersed by wind.
Shade and shelter
Excellent low-level cover in windbreaks.
Useful for controlling gully erosion as fibrous roots bind soil.
Timber pale, fine-grained and tough. Seasons well due to little shrinkage. Takes fine polish and has pleasant scent when freshly cut.
Useful habitat as bursaria hosts insects that feed on saw-fly larvae (spit-fire grubs) which feed on eucalypts. Also a nectar source for wasps that parasitise leaf-eating scarab insects and pasture grubs, generally within 200 metres of plants. Fragrant flowers attract butterflies, moths and other native insects. Insect-eating birds attracted. Thorny plants excellent refuge and nest sites for small birds.
Excellent ornamental or specimens for hedges and cut flowers, due to summer flowering and bronze capsules over winter.
Leaves contain aesculin, substance thought to absorb ultraviolet rays. European settlers apparently used it to prevent sunburn. There was industry based on collection of leaves for sunburn creams and haemorrhoid treatment. Nectar can be sucked from flowers.