Bursaria spinosa
Australian blackthorn
Overview
Bursaria spinosa, called sweet bursaria or Australian blackthorn, is a spiny evergreen shrub to small tree of the family Pittosporaceae, found across much of Australia. Depending on conditions it stands 6-20 feet (2-6 m) tall and 6-15 feet (2-4.5 m) wide, with arching, much-branched stems carrying sharp spines and small, dark green, spoon-shaped leaves under 1 inch (25 mm) long. In summer the branch tips fill with large pyramidal sprays of small, white, honey-scented flowers that draw great numbers of bees, butterflies, and other insects. The flowers ripen into flattened, purse- or heart-shaped brown seed capsules that hang on the plant well into autumn. B. spinosa grows in open forest, woodland, grassland, and along watercourses on a wide range of well-drained soils, and tolerates drought, frost, and coastal exposure. The branches are densely thorny, which limits planting near paths but makes the shrub a refuge and nesting site for small birds. It can sucker and spread on disturbed ground, and its size and spines call for room.
Native Range
Native across Australia, from Queensland and New South Wales through Victoria, Tasmania, and South Australia to Western Australia. It grows in open forest, woodland, grassland, and riverbanks on many soil types.Suggested Uses
Grown as a hedge, screen, or habitat shrub in native and dryland gardens, and used in revegetation and shelterbelts. Its summer flowers feed pollinators, including rare butterflies that depend on it, and the thorny growth shelters small birds. The flowers were once distilled for a sunscreen compound.How to Identify
Appearance
Size & Dimensions
Height6' - 20'
Width/Spread6' - 15'
Bloom Information
Flowering peaks in summer, around December to February in its native range. The dense sprays of small white flowers are sweetly honey-scented and attract bees, butterflies, beetles, and many other insects. Bloom can last several weeks and is followed by persistent brown capsules.
Detailed Descriptions
Foliage Description
dark greenGrowing Conditions
Sun Requirements
Requires 5-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Plants grow in full sun to part shade on almost any well-drained soil and tolerate drought once established. Water young plants until rooted, after which little watering is needed. The shrub withstands frost and coastal salt but rots in constantly wet ground. No special feeding is needed, and lean soils suit it. It can be slow to establish but is long-lived and tough thereafter. Seedlings and root suckers may appear around mature plants on open ground.Pruning
Pruning after flowering shapes the shrub, lifts the canopy of a small tree form, and removes dead or crossing wood. It tolerates hard cutting and reshoots from old wood. The dense spines make all pruning slow and call for stout gloves.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
summerfall