Arum lily (Zantedeschia aethiopica)

Arum lily is an ornamental plant with large white flowers. All parts of the plant are poisonous to people and animals.

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How does this weed affect you?

Arum lily is a garden escape that has spread to wetlands, other natural areas and pastures. It:

is toxic to people, livestock, pets and native animals
can choke waterways
reduces pasture productivity
outcompetes native plants.

Human poisoning

Arum lily contains a mineral called calcium oxalate. All parts of the plant, especially the flower, are poisonous and can cause:

eczema and dermatitis
irritation, burning and swelling of the mouth and throat
breathing difficulties
severe nausea, vomiting and stomach pain
diarrhoea
shock and exhaustion
death.

What to do if a person is poisoned:

If the patient is unconscious, unresponsive or having difficulty breathing dial 000 or get to the emergency section of a hospital immediately.
If the patient is conscious and responsive call the Poisons Information Centre on 13 11 26 or your doctor.

Livestock poisoning

It is not common for livestock to eat arum lily plants, but death can occur if they do. When ruminants (sheep, cattle and horses) eat arum lily it can cause:

irritation, burning and swelling of the mouth and throat
excessive drooling
vomiting
difficulty swallowing.

Poisoning of other animals

Arum lily can also be toxic to dogs, cats and birds. If you think you have affected animals contact your vet.

What does it look like?

Arum lily is a long-lived plant that is 1-1.5 m tall. It is known for its large, white flowers and recognisable leaves. New leaves grow from underground stems in autumn, followed by flowers in winter. Plants yellow off in areas with dry summers. In wet areas the plant is green year-round.

Other varieties of arum lily are also invasive, including a green flowered version called ‘Green Goddess’.

Leaves are:

dark green and glossy
large (13-50 cm long, 8-25 cm wide)
leathery, often with wavy edges
arrow-shaped at the tip
heart-shaped at the base
attached to thick, fleshy stalks (40-150 cm long).

Flowers are:

10-26 cm long and 8-15 cm wide
funnel-shaped, with a backwards pointing tip
white, with a central yellow or orange spike
present from winter to early summer.

Seeds are:

yellowy-brown
3 mm wide
small and round
short lived
numerous, with single plants producing thousands per year.

Fruit are:

green-yellowish berries that are orange when ripe
oval-shaped
0.5-1 cm wide
clustered in groups of 40-50
often hidden in the flower base
ripe in summer.

Seeds are:

yellowy-brown
3 mm wide
small and round
short lived
numerous, with single plants producing thousands per year.

Stems are:

up to 1.5 m tall
smooth and fleshy
attached to flowers.

Roots are:

fleshy, horizontal stems called rhizomes
large.

Similar looking plants

Arum lily looks similar to:

Native cunjevoi (Alocasia brisbanensis), which has narrow, green flowers and spade-shaped leaves.
Taro (Colocasia esculenta), which has green-yellow flowers and green berries (rare).
Italian arum (Arum italicum), which has green flowers, red berries and white and green spotted leaves.

Where is it found?

Arum lily is an environmental weed in Western Australia, South Australia, Tasmania, New South Wales and south-east Queensland. It is common in coastal areas of NSW. It is most invasive on Lord Howe and Norfolk Islands.

This plant is native to South Africa. and was brought to Australia as a garden ornamental.

What type of environment does it grow in?

Arum lily prefers wet, sunny areas but can also grow in full shade. It is hardy and can tolerate waterlogging, fire, occasional frost and salt. It can grow in tropical and cold areas, but does not grow well in dry conditions.

Plants can grow in:

waterways and creek banks
wetlands and swamps
moist pastures
coastal areas
gardens
disturbed areas such as rubbish dumps and roadsides
bush land.

How does it spread?

Arum lily spreads by plant parts and seed. It is also spread by gardners as it is available in nurseries, plant markets and online.

By seed

Plants may take 3 to 4 years before producing viable seed. Seeds germinate in late autumn to winter. They can be spread by water, contaminated soil, animals including birds, foxes and livestock and by people dumping garden waste.

By plant parts

New plants can grow from roots, or root fragments. They spread out from original plants forming larger clumps. Long distance spread of roots can be by water, moving contaminated soil or by people dumping garden waste.

References

Everist, S.L. (1981). Poisonous Plants of Australia Revised ed, Angus and Robertson, Sydney.

Moore, J. H., & Hoskins, E. B. (1997). Arum lily Zantedeschia aethiopica control in the south west of Western Australia. In Proceedings of Arum lily workshop held at HMAS Stirling, Garden Island. CRC for Weed Management Systems, Adelaide, Australia (pp. 31-37).

Panetta, F.D. (1988). Studies on the seed biology of arum lily (Zantedeschia aethiopica (L.) Spreng.). Plant Protection Quarterly 3(4):169-171.

Parsons, W.T. and Cuthbertson, E.G. (2001). Noxious weeds of Australia. (Inkata Press, Melbourne).

Richardson, F.J., Richardson, R.G. and Shepherd, R.C.H. (2016) Weeds of the south-east: an identification guide for Australia (3rd Ed). R.G. and F.J. Richardson, Meredith, Australia.

Scott, J. K., & Neser, S. (1996). Prospects for the biological control of the environmental weed, Zantedeschia aethiopica (arum lily). In Proceedings of the 11th Australian Weeds Conference, Melbourne, Australia, (pp. 413-416).

More information

Control

Successful weed control relies on follow up after the initial efforts. This means looking for and killing regrowth or new seedlings. Using a combination of control methods is usually more successful.

Arum lily can be hard to control because of its large, hardy root system. Efforts should be repeated over several years to run down the plant’s root system.

Prevention and early detection

Avoid moving soil, vehicles and machinery contaminated with arum lily. Learn to identify arum lily and remove plants early to reduce the chance of spread. Small plants are easier to dig up.

Cultivation

Rotary hoeing can be used to control arum lily. Repeat efforts over a few years will be needed.

Physical removal

Plants can be dug up by hand. Remove as much of the root system as possible and follow up for a few years to make sure no roots remain. Remove flowers as soon as possible to stop the plant from seeding, if digging out the plants is delayed.

Contact your local council for advice on how to dispose of arum lily.

Chemical control

Spraying

Spray actively growing plants. The best time to spray is June to October, especially when the plants are flowering. Ensure that all of the foliage is covered with herbicide.

Splatter guns

Splatter guns can be used for dense infestations of weeds that are difficult to reach. The specialised nozzle produces large droplets that allow plants up to 10 m away to be sprayed with limited chance of spray drift. Spray small amounts of concentrated herbicide onto the weeds. It is not necessary to cover all of the foliage.

Wiping

Wipers or wands can be used to apply the herbicide mix directly onto arum lily leaves. This reduces damage to desirable plants.

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 31/03/2025
Fluroxypyr 200 g/L (Various products)
Rate: 500 mL - 1 L per 100 L water
Comments: Spot spray
Withholding period: Do not graze failed crops and treated pastures or cut for stock feed for 7 days after application. See label for further information.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

PERMIT 9907 Expires 31/03/2025
Fluroxypyr 333 g/L (Starane™ Advanced)
Rate: 300 to 600 mL per 100 L water
Comments: Spot spray
Withholding period: Do not graze failed crops and treated pastures or cut for stock food for 7 days after application. See label for more information.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Various products)
Rate: One part product to 50 parts water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Various products)
Rate: One part product to 9 parts water
Comments: Splatter gun
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Various products)
Rate: One part product to 20 parts water
Comments: Wipe onto leaves
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

PERMIT 9907 Expires 31/03/2025
Metsulfuron-methyl 600 g/kg (Various products)
Rate: 10 - 20 g per 100 L water plus surfactant
Comments: Spot spray
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors)
Resistance risk: High

PERMIT 9907 Expires 31/03/2025
Metsulfuron-methyl 600 g/kg (Various products)
Rate: 10 g per 1 L of water plus surfactant
Comments: Wipe onto leaves
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors)
Resistance risk: High

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 pest 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.

For technical advice and assistance with identification please contact your local council weeds officer.

Reviewed 2019