Quick Facts

Quick facts

• Yellow Oleander (Cascabela thevetia) is a spreading large shrub or small tree.
• All parts of the plant are highly toxic if eaten.
• It invades native vegetation and impacts on the biodiversity of Australian rangelands.
• It is naturalised in natural communities and disturbed habitats in Queensland, Northern Territory, Western Australia and New South Wales.

What Does It Look Like?

What is it?

Yellow Oleander (Cascabela thevetia) is a large spreading shrub or small tree growing to 4 m high with milky sap. The leaves are more or less lance-shaped, 5.5 to 15 cm long by 0.5 to 1.5 cm wide and arranged alternately along the branchlets. The upper surface of the leaves is glossy, dark green with the lower surface pale green. The leaf stalk is 1 to 3 mm long. The sweetly perfumed flowers are grouped in clusters at the end of the branches with each flower on a stalk 2 to 4 cm long. The flower is funnel-shaped, yellow or peach-orange in colour and 5.5 to 7 cm long by 2.5 to 4 cm across. The fruit are oval, egg-shaped or broadly triangular in outline, 2 to 2.7 cm long by 2.8 to 3 cm wide. The outer coat of the fruit is fleshy and green when immature, becoming black when ripe and encloses a hard 'stone' with two starchy kernels (Everist 1974; Forster 1996; Queensland Poisons Information Centre 2008).

For further information and assistance with identification of Yellow Oleander, contact the herbarium in your state or territory.

Flower colour

Yellow, Orange

Growth form (weed type/habit)

Tree, Shrub

Where it currently grows? Preferred habitat

In Australia, Yellow Oleander has been recorded growing in riparian open forest or woodland communities along watercourses and floodplains on sandy to clay soils, and in neglected areas around towns and roadsides (Forster 1996; Queensland Herbarium 2008). Yellow Oleander will grow on most soil types, but prefers fertile, well-drained soils (Csurhes & Edwards 1998).

Are there similar species?

Yellow Oleander is very distinctive with its large funnel-shaped, yellow or peach-orange flowers and fleshy fruit that are green but becoming black when ripe and is not commonly confused with other species (Jordan 2007).

Why Is It A Weed?

What are its impacts?

Yellow Oleander invades native vegetation and impacts on the biodiversity of Australian rangelands (Martin et al. 2006; Jordan 2007). All parts of Yellow Oleander are highly toxic if eaten by humans or grazing animals, particularly the fruit and seeds. However, most grazing animals refuse to eat the plant under normal circumstances. The sap may be an irritant and cause dermatitis or blistering (Everist 1974; Queensland Poisons Information Centre 2008).

How does it spread?

Yellow Oleander produces large fleshy fruit with two to four seeds (Forster 1996). The primary means of spread is through human horticultural activities as Yellow Oleander is a popular garden and urban ornamental plant.

What is its history in Australia?

It is not known exactly when and where Yellow Oleander was first introduced into Australia. It was recorded growing in the Brisbane Botanic Gardens in 1875 and has been a popular garden ornamental, street or park tree in tropical and subtropical regions (Hill 1875; Forster 1996; Shepherd 2004).

How To Manage It?

Best practice management

Yellow Oleander can be controlled by grubbing and hand pulling seedlings. Larger trees need to be felled (Smith 2005).

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Yellow Oleander is a perennial shrub that flowers and fruits throughout the year (Forster 1996).

Where Is It Found?

Which states and territories is it found?

NSW, NT, QLD, WA

What areas within states and territories is it found?

Yellow Oleander occurs along the east coast of Australia from near Cairns in Queensland south to Grafton in New South Wales. There are also scattered populations in inland Queensland, the northern parts of the Northern Territory and the Kimberley in Western Australia (Harden 2007; Queensland Herbarium 2008).

Where does it originate?

Yellow Oleander is probably native to Mexico (GRIN 2008). It is now widely cultivated in tropical and subtropical regions of the world (Everist 1974).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

QLD, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Cascabela thevetia

Other scientific names (synonyms)?

• Cascabela peruviana (Pers.) Raf.
• Cerbera peruviana Pers.
• Cerbera thevetia L.
• Thevetia peruviana (Pers.) K.Schum.

Does it have other known common name(s)?

Captain Cook Tree, Lucky Nut, Be-still Tree, Cook Tree, Tree Daffodil, Dicky Plant