Quick Facts

Quick facts

• Green Cestrum (Cestrum parqui) is a shrub with dark olive-green leaves and pale yellow tubular flowers.
• It is found in subtropical to temperate areas of southern Australia.
• It is toxic to stock and humans.
• It can be difficult to control because it has radiating shallow roots (of varying extent) that produce suckers.
• It is an agricultural, urban and environmental weed.

What Does It Look Like?

What is it?

Green Cestrum (Cestrum parqui) is a shrub to 3 m high, often with multiple branches from the base; the branches are pale grey-brown and brittle.  As well as a taproot there are shallow horizontal roots (deep yellow in colour) radiating from the base of each plant, giving rise to suckers some distance away in favourable conditions.  The new growth is finely hairy, but these hairs are soon lost. The leaves are alternate along the branches, mid to dark olive green, shortly stalked, lanceolate (lance-shaped) or narrowly elliptic (widest at the middle), narrowly tapered at both ends, mostly 30–65 mm long and 8–23 mm wide, sometimes up to 100 x 30 mm; they are foul-smelling when handled.

The flowers are borne in dense clusters at the ends of the branches; they are pale yellow to greenish-yellow, narrowly trumpet-shaped with 5 short triangular teeth at the top, overall 15–23 mm long, sweetly scented at night but with an unpleasant odour during the day. There is a short, 5-toothed calyx (outer covering) extending for 5 mm up the flower tube from the base.

The fruit is a deep purple to black ovoid (egg-shaped) fleshy berry, 10–15 mm long and containing several chunky seeds 3.5–4 mm long (Purdie et al. 1982; Stanley & Ross 1986; Thorp & Wilson 1998; Land Protection 2007).

For further information or assistance with the identification of Green Cestrum contact the herbarium in your state or territory.

Flower colour

Pale yellow to greenish yellow

Growth form (weed type/habit)

Root-suckering shrub

Where it currently grows? Preferred habitat

Green Cestrum is widely though sporadically naturalised in south-eastern Australia, usually where annual rainfall exceeds 1000 mm per year. It prefers open disturbed habitats where moisture is available, for example along streams, in suitable urban bushland or wasteland and along roadsides. It is often found as a weed in domestic and municipal gardens.  Green Cestrum prefers loamy or clayey soils (Parsons & Cuthbertson 2001; AVH 2021).

Are there similar species?

Green Cestrum is similar to the sparingly naturalized Lady of the Night (Cestrum nocturnum), but the latter has white berries and flowers that are very slender (the tube only 1–3 mm wide);  Green Cestrum has purple-black berries and flower tubes 3–5 mm wide (Purdie et al. 1982). 

Why Is It A Weed?

What are its impacts?

Agriculture: Green Cestrum is a recognised agricultural weed because it is toxic to stock. Cattle, sheep, horses, pigs and poultry are known to be affected and can die within hours if they consume parts of the plant. Stock are often vulnerable when they gain access, along fence-lines, to plants of this species growing in gardens or as a weed in vegetation along stream banks or roadsides. Its effect on native fauna is unknown (Land Protection 2007). 

Human impacts: Green Cestrum is toxic to humans (GISD 2006).

Native ecosystems: Green Cestrum can be a vigorous invader of native ecosystems; it has a considerable impact on the structure and composition of coastal woodlands in Victoria and is known to out-compete most other vegetation on alluvial flats in Queensland (Parsons & Cuthbertson 2001; Land Protection 2007). Dense stands can inhibit access to waterways, and prevent establishment of native plants in the vicinity (Muyt 2001).

How does it spread?

The seeds of Green Cestrum are dispersed by birds. Root segments can be spread in soil transported by earth-moving equipment and carried by floodwater, with this form of dispersal probably accounting for spread along some riverbanks (Parsons & Cuthbertson 2001).

What is its history in Australia?

Green Cestrum was originally introduced as a garden ornamental and first became naturalised in Australia in the 1920s. It was recorded in the Brisbane Botanic Gardens in 1924 and naturalised at Ashgrove, a suburb of Brisbane, in 1926 (Parsons & Cuthbertson 2001; AVH 2021). Naturalised occurrences were first recorded for Victoria in the early 1940s (Parsons & Cuthbertson 2001). New infestations distant from previous occurrences have probably occurred as a result of escape from gardens following planting as an ornamental in a new location.

How To Manage It?

Best practice management

Non-chemical control: Effective mechanical control can be achieved by removing plants before flowering and fruiting and before formation of extensive horizontal roots; this helps prevent spread by birds eating the berries as well as from suckering. Removal of plants by bulldozing is effective and may be appropriate in some situations. Regrowth must be monitored and either mechanically removed or sprayed. Plants should be carefully removed to ensure all root material is taken to prevent regrowth. Seedlings may be suppressed by competition with other plants in suitable areas (Parsons & Cuthbertson 2001; Land Protection 2007).

Chemical control: Herbicides can be effective in controlling Green Cestrum (Parsons & Cuthbertson 2001; Land Protection 2007). Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Green Cestrum is a perennial plant. It germinates in autumn but flowers are not produced until the plant is at least two years old. It flowers for several months, from spring to autumn. In cooler areas plants may be partly deciduous in winter. The seeds remain dormant in the soil for many years (Parsons & Cuthbertson 2001; Crawford & Wollondilly Shire Council 2006; Land Protection 2007).

Growth Calendar :http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0005/154508/calendar-weeds-wollondilly.pdf 

Where Is It Found?

Which states and territories is it found?

NSW, QLD, SA, TAS, VIC, WA

What areas within states and territories is it found?

Green Cestrum is sparingly naturalised in south-western Western Australia (Perth only); mainly in Adelaide and in country towns in the more southern (temperate) regions of  South Australia; chiefly in Melbourne and near Bairnsdale as well as some scattered sites in Victoria, on King Island only in Tasmania, extensively along the east coast of New South Wales as well as some rivers of the western slopes of the Great Divide and in Queensland mainly in the south-east, from the Gold Coast to Rockhampton, with scattered occurrences inland to Roma (Purdie et al. 1982; Parsons & Cuthbertson 2001, AVH 2021).

Where does it originate?

Green Cestrum occurs naturally in Argentina, Brazil, Bolivia, Chile, Paraguay, and Uruguay (GRIN 2008).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, VIC, 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

Cestrum parqui

Other scientific names (synonyms)?

Does it have other known common name(s)?

Green Poisonberry, Chilean Cestrum, Black Nightshade, Chilean Jessamine, Willow Leaved Jessamine