Cow Itch Tree
Lagunaria patersonia
NEMBA: Scrutiny advised
English: Cow Itch Tree, Norfolk Island Hibiscus, Pyramid Tree, Queensland White Oak, Sally Wood, Primrose Tree, Itchy Bomb Tree
Synonyms: Hibiscus patersonii, Laguna patersonia, Laguna squamea, Solandra squamea
Historical botanical names: Hibiscus patersonii
Lagunaria patersonia, commonly known as Norfolk Island Hibiscus or Pyramid Tree, is an evergreen tree or large shrub valued for its exuberant pink to mauve hibiscus-like flowers and pyramidal form. It produces distinctive hairy seed capsules that burst open to release irritating fibres, earning it names like “itchy bomb tree” and “cow itch tree.” Though ornamental, it can naturalise in coastal South Africa and pose both a nuisance and health hazard.
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Distinguishing features:
Evergreen oval leaves 5–10 cm long with silvery-hairy undersides, turning grey-green when mature
Hibiscus-style flowers 4–8 cm across, pale pink to mauve fading to white, borne singly or in pairs in leaf axils
Stamen column prominent, with numerous golden-orange anthers
Hard, spherical to ovoid seed capsules 2–4 cm long, splitting into five valves to release seeds and fine white hairs that cause skin irritation
Smooth dark grey bark, may develop fissures in mature trees
Pyramidal canopy, branches often from low on trunk
Origin:
Native to Norfolk Island, Lord Howe Island, and north-eastern Australia, including Queensland and New South Wales
Overall appearance:
Evergreen tree, pyramidal in sheltered sites, reaching up to 20 m. In exposed coastal areas, canopy may become wind-distorted
Height:
10–20 m
Width:
10–12 m
Leaves:
5–10 cm long, 2.5–5 cm wide
Elliptic to ovate with smooth margins, blunt or rounded tip
Upper surface olive to grey-green, under surface silvery tomentose when young, becoming smooth
Petiole up to 3 cm long
Flowers:
Diameter 4–8 cm
Five waxy petals, pink to mauve, fading to pale or white
Arranged singly, occasionally in pairs, on thick pedicels 1–2 cm long
Stamen filaments fused into a central column with golden to orange anthers; tip has 3‑5 teeth
Flowering season:
Spring to early summer; often sporadic blooms through warmer months
Fruits:
Spherical loculicidal capsules 2–4 cm long, splitting into five valves
Outer surface grey‑brown with dense scales and hairs
Contain dense white irritating hairs and smooth orange‑red to reddish‑brown seeds ~6–7 mm long
Seeds:
Kidney-shaped, ~6 mm long, contained within capsules among irritating hairs
Bark:
Dark grey, smooth initially, may develop shallow fissures with age
Stems:
Young twigs covered in dense scales and hairs; branches low on trunk
Soil type:
Tolerates sandy, loamy, clay loams; well-drained preferred; salt spray tolerant
Aspect:
Prefers full sun; thrives in coastal and wind-exposed sites; tolerates light frost (~–5 °C)
Edibility:
Not edible; handling seed pods causes skin irritation
Toxicity:
Seed hairs cause skin and eye irritation; fibres act like fiberglass splinters
Uses:
Ornamental: flowering specimen, hedges, street and coastal planting
Windbreak and salt-tolerant screen
Aboriginal use: fibres from bark or pods used for baskets, nets, ropes
Ecology:
Attracts pollinators such as bees and lorikeets
Hibiscus Harlequin Bug feeds on leaves, flowers, fruits, seeds
Produces persistent seed bank; seeds spread via water and garden waste
Distribution and habitat:
Naturalised in South Africa’s coastal regions (notably Western Cape)
Found along roadsides, disturbed coastal habitats, gardens
Also naturalised in Australia beyond native range, California, New Zealand
Derivation of name:
Lagunaria honours Andrés de Laguna, Spanish botanist
'patersonia' commemorates Colonel William Paterson, who sent seeds to England
Common name “Cow Itch Tree” refers to irritating seed hairs, not cattle
Historical aspects:
Described as Hibiscus patersonii in 1803; transferred to Lagunaria genus in 1828; subspecies from Queensland elevated to separate species in 2006
Interesting facts:
The seed capsule hairs are so irritating they’ve been likened to “fibreglass splinters”!
Aboriginal people used its strong fibres for making nets and ropes.
Though called a “bomb tree”, it doesn’t explode—its seed pods simply burst open and puff out hairs.
Flowers shift colour as they age—from deep pink to white—offering a multi-toned display.
It’s named after botanists from the 1500s and 1700s—a tree with serious historical roots!
Friendly alternatives:
Common name
Scientific Name
Plant type:
Plant type
Plant family:
Malvaceae (Latin plant name) - Order: Malvales