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Weed of the Month -Green cestrum

 Cestrum parqui L’Hérit

Green cestrum is related to well known species such as tomato, potato and tobacco.
It was originally introduced into Australia from South America as an ornamental shrub and is now naturalised in the Hunter region. You will normally see green cestrum along watercourses and in urban areas.

It can grow up to 3 meters in height. Its shiny-green leaves are around 25 mm wide, 100 mm long, and produce a very pungent smell when crushed. Green cestrum is starting to bud now and has a long flowering time (late spring to autumn). The small trumpet shaped flowers are found in clusters at the ends of branches. They are normally yellow but may have a green tinge. These are followed by small, shiny black, egg-shaped berries.

Problem:
Green cestrum is poisonous.  Poisoning is most commonly seen in cattle when there is a shortage of available green feed. Even small quantities of leaves, twigs or fruit (even dry leaves from plants which have been cut down or sprayed) can cause death, which is usually rapid and painful. The plant is also known to be toxic to other livestock and humans.

Vectors:
Green cestrum is still spread through garden clippings. Where it has naturalised it is spread by birds that are able to eaten the berries, or along watercourses during floods.

Physical control:
Plants can be controlled by repeated cutting or physical mechanical removal. Green cestrum will sucker freely from its base if stumps are not treated after cutting. The plant will also grow from sections of the fleshy root which remain after a plant has been partly dug or pulled-out.

Herbicide control: Both regrowth and new seedlings will need to be sprayed as a follow up treatment.
A number of herbicides are registered for control. Always read the label carefully and use only as directed.

Green cestrum is a declared noxious weed throughout most of New South Wales.