Cecropia (Cecropia species)

Profile

Impact

Cecropia are fast-growing pioneer species that have the potential to become serious weeds of wetter forest and riparian habitats across much of northern Australia and parts of southern coastal Australia.

Cecropia quickly invade and form dense colonies in forest gaps and edges, riparian areas, roadsides and other disturbed areas. The dense stands impede the growth of other species. Although cecropia don’t survive in shaded areas, they produce large seed banks which aid their spread and persistence in the environment.

They are significant weeds of forested areas in other parts of the world and are rated in the top 100 of the world’s worst weeds in the Global Invasive Species Database.

Distribution

Cecropia are native to southern Mexico, Central America and the West Indies and have become naturalised in tropical Africa, tropical Asia and on some Pacific islands. They are widely cultivated as ornamental plants in subtropical and tropical areas of the world, including Australia. 

They have become sparingly naturalised in northern and south-east Queensland and northern New South Wales. They are also naturalised in tropical Africa, tropical Asia and on some Pacific islands. In NSW approximately 45 cecropia trees have been found near Lismore, Burringbar and Murwillumbah, planted mainly as ornamental trees. Numerous seedlings have also been found surrounding sites with mature male and female trees.

Spread

Cecropia are spread by seed, mostly when birds and bats eat the fruit. Some spread may occur through flowing water and transportation of seed-contaminated soil.

Seed production is very high and large soil seedbanks can result, but seeds are only viable for a few months.

Dumping of plant material in garden waste may also be responsible for some spread, as stem sections have been shown to form roots.

Seed germination can be prolific in canopy gaps and open areas, and seedlings are especially light-demanding.

Cecropia are rapidly growing, short-lived, pioneer trees that grow mostly over the warmer months. Flowering can occur throughout the year, but usually peaks early in the wet season. 

Description

Cecropia are trees mostly 6-20 m tall, but can extend from 5-40 m tall. Trunks usually have little branching low down and stilt roots may be present, especially on large trees growing near water.

Younger stems are hollow and have triangular leaf scars. When branches are cut they release a watery-mucilaginous sap that turns black on exposure to the air.

Leaves are large (to 60 cm long), circular and deeply palmately-lobed (7-15 lobes) they are spirally arranged. The upper side of the leaves are dark green, while the underside is covered in whitish hairs.  Leaf stalks are attached to the underside of the leaves towards their centre.

There are separate male and female plants. Male flowers occur in clusters of 3-50 cylindrical, yellowish spikes 2.5-18 cm long. Female flowers occur in clusters of usually 2-6 cylindrical greenish or greyish-green flower spikes 3-30 cm long. Fruit are inconspicuous, fleshy and 3-4 mm long.

Habitat

Cecropia prefer tropical climates, but will grow in subtropical and warm temperate areas.

They are best adapted to disturbed sites with plenty of light and moisture, and where the soil is fertile.

Seeds rarely germinate under dense canopies, but can be prolific in canopy gaps. Plant growth is poor in shaded areas and plants will not persist in the shade.

They are potential weeds of closed-forest gaps and margins, riparian areas, gullies, roadsides, abandoned farmland, wasteland and other disturbed areas.

Acknowledgements

Author: Harry Rose

Reviewers: Rod Ensbey, Elissa van Oosterhout

References

Australia’s Virtual Herbarium: Broussonetia papyrifera. http://avh.ala.org.au/occurrences/search?taxa=Cecropia#map 

Bisbane City Council Weed Identification Tool: Trumpet Tree (Cecropia palmate/peltata). http://weeds.brisbane.qld.gov.au/weeds/trumpet-tree-cecropia-palmata-peltata 

Csurhes, S. (208). Pest plant risk assessment Cecropia (Cecropia spp.). Queensland Department of Primary Industries. http://www.daff.qld.gov.au/__data/assets/pdf_file/0011/68969/IPA-Cecropia-Risk-Assessment.pdf 

Far North Coast Weeds Weed Information: Cecropia peltata. http://fncw.nsw.gov.au/weed-information/new-and-emerging-weeds-index/cecropia-peltata/

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Control

Cecropia are Regionally Prohibited, notifiable noxious weeds in a number of coastal areas. This prohibits their sale and distribution and requires that plants must be eradicated from the land and that land must be kept free of the plant.

Suspected cecropia plants should be reported to the local council weeds officer, who will provide positive identification, and assistance and advice with removal and control.

Herbicide options

WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au

See Using herbicides for more information.


PERMIT 9907 Expires 31/03/2020
Glyphosate 360 g/L (Roundup®)
Rate: 1 part glyphosate to 1.5 parts water
Comments: Cut stump aplication
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


Picloram 44.7 g/kg + Aminopyralid 4.47 g/L (Vigilant II ®)
Rate: Undiluted
Comments: Cut stump application. Apply a 3-5 mm layer of gel for stems less than 20 mm. Apply a 5 mm layer on stems above 20 mm.
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area Duty
All of NSW General Biosecurity Duty
All plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.
North Coast Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfill the general biosecurity duty for this weed click here

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Reviewed 2017