Green Cestrum

Cestrum parqui

Family: Solanaceae

Type of weed:

Flowering Months: , , , , , ,

Description

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.

Dispersal

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.

Distribution

. Lower and Mid Mountains along river systems; found in Springwood, Warrimoo, Glenbrook and Blaxland.

Alternative planting

Native plants

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.

There are native nurseries in several Blue Mountains villages, including Glenbrook, Lawson and Katoomba. Please also ask at your favourite local nursery.

Control

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 more info

For key points on these techniques: