Family: Solanaceae

Status: Declared noxious in Bega Valley, Eurobodalla and the Shoalhaven in category W2, meaning that it must be fully and continuously suppressed and destroyed.

Description:
A straggly evergreen shrub 2-4m high with arching stems. Leaves are alternately arranged on the stems, dark green and slightly shiny above and paler below, with slightly wavy margins and a pointed tip, 7-14cm long. The prominent central vein on each leaf is yellow and strongly raised on the underside, particularly near the leaf base. The leaves have a very unpleasant smell when crushed, although it is possible to find the odd specimen without this characteristic. Flowers are tubular, about 2cm long, with the petals flared at the tip. They are yellow-green in colour and occur in dense elongated clusters at the branch tips. Fruits are succulent, about 1cm across, and round or oval. They ripen from green to black.

Preferred habitat and impacts:
More common in the north of the region, but occasionally found as far south as the Bega Valley. Found in dry and wet eucalypt forest and rainforest, where it can dominate the understorey and prevent regeneration by native plants. The plant is poisonous to both livestock and humans. Handling cestrum may cause contact dermatitis in some people.

Dispersal:
Birds, dumping of plants carrying seed.

Look-alikes:
The foliage of cestrum is not particularly distinctive and could probably be confused with some native shrubs of wet eucalypt forests and rainforest, but if the flowers are present the plant should be recognisable. The strong unpleasant smell of the crushed leaves is unmistakeable, but the occasional plant can be found which does not have this smell.
The flowers of green cestrum are sweetly scented at night. A related and very similar species, lady-of-the-night (Cestrum nocturnum ) is promoted as a garden plant for its strongly perfumed flowers, and the two plants could easily be confused. Lady-of-the-night has larger leaves (10-15cm by 4-7cm wide compared with 2-7cm by1-3cm in green cestrum) and white rather than purple berries. It has not been found to naturalise as readily as green cestrum, but being a bird-spread species should be avoided in the garden.
Two other Cestrum species are also occasionally naturalised in the northern part of the region, from garden plantings. They are red cestrum (Cestrum elegans ) which has red flowers and berries, and orange cestrum (Cestrum aurantiacum ) which has orange-yellow flowers and white berries. They should not be planted in the garden.

Control:
Seedlings may be hand pulled or dug out. Cut and paint or stem inject mature plants, preferably before they begin to develop seed. To improve the effectiveness when using the cut and paint method, peel the bark back all around the stump and apply herbicide quickly to both the cut face and the exposed outer wood. Spray with selective herbicides. Follow-up treatment will be needed on seedlings.