About Us
Weed Alerts
Declared Noxious Weeds
African boxthorn
Bitou Bush
Cape or Montpelier Broom
Gorse or furze
Green Cestrum
Groundsel bush
Harrisia Cactus
Karoo thorn
Kochia other than Summer or Mock Cypress
Koster's curse
Mysore thorn
Prickly Pear other than Indian Fig
Scotch or English Broom
Siam Weed
Spanish broom
Sweet briar or briar rose
Tropical soda apple
Noxious Weeds Act
Plans and Strategies
Weed Resources

Mysore thorn

Mysore thorn

Mysore thorn2

Mysore thorn3

Bird of paradise flower

Senna pendula

Senna multiglandulosa pods

Senna septemtrionalis flower

Cape wattle flower

Cape wattle bipinnate leaf

Cape wattle pods

Maclura cochinchinensis juvenile foliage1

Maclura cochinchinensis juvenile foliage2


Caesalpinoidae subfamily in Fabaceae (peas)


Mysore thorn or thorny poinciana (Caesalpinea decapetala) is listed as noxious in Class 3 only in Illawarra LCA within the Southern Tablelands and South East Region.


Mysore thorn is an erect shrub or climber with stems covered in backward pointing prickles 0.5-5mm long. It has a bipinnate (ferny) leaf 7-40cm long with 4-10 pairs of sub-leaves each carrying 5-12 pairs of quite large leaflets (7-18mm long). The leaflets are blue-green, finely hairy on both surfaces, paler on the underside and the leaf stem is prickly. At the base of each leaf is a distinctive lobed oval shaped structure called a stipule. The cream flowers are produced in winter and spring and are carried in large branched terminal clusters. They have 5 petals which are about 10mm long. The fruit is a pod, oblong, flat and hairy with 6-9 oval seeds. The first 3 photos (provided by Forest & Kim Starr of USGS, Hawaii) are of this species. View more photos of Mysore thorn and more information on the fact sheet link below.

preferred habitat and impacts

An occasional garden escape which is found on roadsides and the margins of rainforest north from the Wollongong area.


Dumped seed-bearing garden waste or movement of seed-contaminated soil.


Bird-of-paradise flower (Caesalpinea gilliesii) is a related
garden plant which occasionally naturalises in moist forest. It has
bipinnate leaves and cream flowers but is distinguished by the lack of
thorns on the stems and the very long protruding red stamens in the
flowers. Flower clusters are more compact than those of Mysore thorn
and the brown seed pods are hairy.

The common garden escape weeds Cassia (Senna species) have pinnate rather than bipinnate leaves (see photos above for the appearance of a pinnate leaf). Their flowers are deep yellow and have conspicuously protruding stamens and style (the reproductive parts of the flower) and the leaves often have a number of small raised glands on the upper surface of the leaf stem between some or all of the leaflet pairs.

Another garden escape weed, Cape or crested wattle (Paraserianthes lophantha, formerly Albizzia lophantha) has very similar blue-green leaves to Mysore thorn but has no thorns and its flowers are small and cream, in fluffy bottlebrush-like spikes in the leaf axils. The fruit is a large, flat, brown, hairless pod with transverse ribs.

There is a native plant of rainforest edges which is a shrub or climber with backward pointing thorns on the stems, Maclura cochinchinensis, but this has much longer thorns, at least 10mm long. Leaves are simple and oval with smooth edges, not compound, though from their arrangement on the stems they may look compound.  Leaf shape is variable, with young plants having round leaves. Thorns are straight, not curved.


For large plants, cut and paint. Seedlings and smaller plants can be hand-pulled or dug out. Seed could be long-lived in the soil and seedling growth after removal of the parent plants will need follow-up work. Spray if seedling growth is prolific, or hand-pull.

Mysore thorn pdf Mysore thorn pdf 147.8 KB