Bursaria spinosa, common names Blackthorn or sweet bursaria, is a medium to large shrub or small tree, growing to 5–10 metres high. Height can vary based on habitat; the coastal forms are known for being rather tall, while those found in subalpine areas can be almost prostrate. It is often multi-stemmed and has a rhizomatous root system, from which is can readily re-sprout after disturbance. The branches are usually spiny. The leaves are small (1–5 cm long), obovate and often clustered on the branches. In spring to summer it produces numerous small (1 cm across) white to cream flowers, which are nicely fragrant. Following this it produces characteristic purse-/heart-shaped seed capsules, inside which, when mature, the seeds rattle in the wind.
The fragrant flowers are known to attract butterflies, and this species is important in the conservation of the Eltham Copper Butterfly in Victoria, whose larvae feed exclusively on the leaves of B. spinosa. The leaves of this species contain a secondary compound called aesculin
(a coumarin glucoside), which was exploited as an ingredient in sunscreens in the 1940s and is used in medical research today.
193.00 Location Many specimens form part of the Tarwin River bank restoration plantings. Planted in 2021.