Common names

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.

Scientific names

Bursaria spinosa.

Family

Pittosporaceae.

Genus

Bursaria.

Name origin

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.

Rainfall

400mm.

Growth rate

Slow.

Growth height

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.

Habitat

Dry or wet sclerophyll forest, on non-siliceous soils.

Habit

Shrub or small tree to about 8m high with leaves green on both surfaces.

Similar species

Distinguish Bursarias by the leaf underside. Sweet Bursaria leaves green on both surfaces. Hairy Bursaria has downy white leaf underside.

Site preference

Well-drained soil. Tolerates frost and wind.

Characteristics

Long-lived. May be slow-growing.

Flowering

White to cream - chiefly summer.

Seed collection

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.

Propagation

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.

Regeneration

From seed over winter. Seed dispersed by wind.

Shade and shelter

Excellent low-level cover in windbreaks.

Land protection

Useful for controlling gully erosion as fibrous roots bind soil.

Timber

Timber pale, fine-grained and tough. Seasons well due to little shrinkage. Takes fine polish and has pleasant scent when freshly cut.

Wildlife

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.

Ornamental

Excellent ornamental or specimens for hedges and cut flowers, due to summer flowering and bronze capsules over winter.

Other

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.