Type of weed: Woody weed
Flower colour(s): Yellow
Green Cestrum is a medium sized perennial shrub growing 2–3 m. It usually has many light green, brittle stems.
The shiny green leaves are 20–30 mm wide and 80–100 mm long. They have smooth edges, are pointed at each end, and produce a pungent, foul smell when crushed.
Cestrum flowers mostly spring to autumn. The flowers are normally yellow but may have a green tinge. They grow in clusters at the end of branches and produce an unpleasant perfume during the day but can smell quite sweet in the evening.
Clusters of green, ripening to shiny, black, egg shaped berries 7–10 mm long are produced during summer and autumn.
Note: Cestrum frequently causes sudden death in livestock and is highly toxic to all animal species, including humans, if eaten.
Spread is most commonly in droppings from birds that have eaten the berries. Seed is also readily spread along watercourses during heavy rainfall.
Impact on bushland
Highly invasive, Green Cestrum is normally found growing along watercourses, where it can produce monocultures.
Lower Blue Mountains. Lower and Mid Mountains along river systems; found in Springwood, Warrimoo, Glenbrook and Blaxland.
Alternative plantings to hold soils on creekbanks or stormwater drainage lines include ferns, sedges and rushes such as:
- Fishbone Water Fern (Blechnum nudum)
- Prickly Rasp Fern (Doodia aspera)
- Common Ground Fern (Calochlaena dubia)
- Broad Rush (Juncus planifolius)
- Common Rush (Juncus usitatus)
- Tall Sedge (Carex appressa)
In drier areas plant:
- Correa spp.
- Oak Leaved Daisy Bush (Olearia quercifolia)
Council provides a tool, on its Mountain Landscapes website, to help you choose native alternative plantings. Choose your village, soil, vegetation community and the purpose of your planting, and the tool will give you suggestions.
- Stem inject or frill
- Scrape and paint
- Cut and paint
- Notify Council
Note: Herbicides that may be used for this weed include .
Stem injection or frilling
At the base of the tree, drill holes at a 45° angle into the sapwood (just under the outer bark) at two finger space intervals around the entire base of the tree. Repeat this process below the lowest branch
As an alternative to drilling, make cuts into the sapwood with a chisel or axe. Fill each cut/hole with herbicide immediately. Repeat the process at 3 cm intervals around the tree.
Plants should be healthy and actively growing. Deciduous plants should be treated in spring and autumn when leaves are fully formed. For multi-stemmed plants, inject or chip below the lowest branch or treat each stem individually. Herbicide must be injected immediately before the plant cells close (within 30 seconds before translocation of herbicide ceases.)
Scrape and paint
With a knife, scrape up to a metre of the stem to reach the layer below the bark/outer layer. Immediately apply herbicide along the length of the scrape.
- A maximum of half the stem diameter should be scraped. Do not ringbark.
- Larger stems (over 1 cm in diameter) should have two scrapes opposite each other.
Cut and paint
Useful for small to medium sized woody weeds up to 10 cm in diameter.
Make a horizontal cut as close to the ground as possible with secateurs or loppers, and immediately apply concentrated Glyphosate to the exposed stump surface. Do not allow the surface to get covered with soil.
Specific control tips for this weed
Berries are bird spread, so treat plants before they fruit. Green Cestrum has a deep and persistent taproot and suckers if it is cut and painted. The most effective method of control is stem injection.
- Small seedlings: dig up if you can remove all the roots.
- Juvenile plants: scrape and paint, making sure that you scrape at least 1/3 of the length of the stem; on larger plants, scrape two sides. Apply herbicide carefully using an applicator bottle immediately on the scraped area.
- Large plants: anything that is large enough to drill or chisel should be stem injected. Exposed roots can also be scraped and painted or injected.
For key points on these techniques:
Regional Priority Weed
- The plant should be eradicated from the land, which must be kept free of the plant.
- The plant should be fully and continuously suppressed and destroyed.