Canna lily (Canna indica)

Also known as: Tous-les-mois, Arrowroot

Canna lily grows up to 2 m tall, has large green leaves and red or yellow flowers. It can outcompete native plants especially in wet areas.

Profile

How does this weed affect you?

Canna lily forms large, dense clumps, particularly along waterways. It:

• outcompetes native plants
• can restrict water movement and increase flooding
• block access to waterways.

What does it look like?

Canna lily is an erect perennial herb up to 2 m tall with fleshy rhizomes.

Leaves are:

• up to 60 cm long and 30 cm wide
• oval-shaped with a pointed tip and sheath at the base
• hairless
• alternate on the stem.

Flowers are:

• red or yellow or occasionally red with yellow spots or yellow with red spots
• showy with 5 petal-like parts each 5–15 mm wide
• in clusters of 6 - 20 flowers at the tips of the flowering stem
• mostly present during spring and summer.

Fruit are:

• capsules covered in wart like bumps
• up to 3 cm long and 2 cm wide
• oval or round
• green or purplish when young
• brown when mature
• mostly present during summer and early autumn.

Seeds are:

• black and smooth
• up to 8 mm long and 7 mm wide
• round or egg-shaped
• very hard.

Stems are:

•  green
• 1-2 m long
• sturdy and upright
• hairless.

Rhizomes:

• branch horizontally
• are up to 60 cm long and 10 cm in diameter
• are made up of fleshy corm-like segments
• have thick fibrous roots.

Similar looking plants

Canna lily looks like other garden canna lilies (Canna x generalis and Canna x orchiodes). However, these plants have much wider petal-like flower parts that are up to 5.5 and 6 cm wide respectively.

Where is it found?

In NSW, most naturalised canna lilies grow along the coast, in high rainfall areas.

Canna lily is native to Central and South America.

What type of environment does it grow in?

Canna lilies grow best in tropical and sub-tropical climates with rainfall above 1000 mm per year. They can tolerate temperate climates but are sensitive to frosts and are not drought tolerant.

Canna lilies grow in a wide range of soil types and can tolerate waterlogged soils. They grow well in moist environments such as on the edges of wetlands and waterways. Plants can grow in full sun or heavy shade.

How does it spread?

Most spread is by gardeners planting canna lily as an ornamental plant.

By seed

Birds eat the fruit and spread the seed. Seeds also spread in floodwaters and by people dumping garden waste.

By plant parts

The thick, branching rhizomes spread out from the base of the plant. Rhizomes are spread by floodwaters and by people dumping garden waste

References

Identic Pty Ltd. and Lucid central (2016). Environmental Weeds of Australia Fact sheet: Canna indica. Retrieved: 19 November 2024 from: https://keyserver.lucidcentral.org/weeds/data/media/Html/canna_indica.htm

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 19 November 2024 from: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Canna~indica

Richardson, F. J., Richardson, R. G., & Shepherd, R. C. H. (2011). Weeds of the south-east: an identification guide for Australia (No. Ed. 3). CSIRO.

Taylor, M. (2024). CABI data sheet: Canna indica (canna lily). Retrieved 20 November 2024 from: https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.14575

More information

back to top

Control

Successful weed control requires follow up after the initial efforts. This means looking for and killing regrowth or new seedlings.

Hand weeding

Young plants may be dug out. Ensure that all of the rhizomes are removed. It is difficult to remove large infestations as plants can regrow from small rhizome fragments left in the soil.

Disposal

Contact your local council for advice on how to dispose of this weed.

Chemical control

Spray

Spray actively growing plants. Ensure that all of the foliage is covered.

Cut and paint

Prune all shoots horizontally at the rhizome and use and apply a 3-5 mm layer of herbicide gel across the cut surface on the rhizome.

If there are more than 4 rhizomes between the shoots:

• drill a 10 mm diameter hole into every fourth rhizome from a shoot
• the hole should go 80% of the way down into the rhizome
• fill the holes with the herbicide gel immediately.

Herbicide options

See Using herbicides for more information.

---

PERMIT 9907 Expires 31/03/2030
Glyphosate 360 g/L (Various products)
Rate: 1 part glyphosate to 50 parts water
Comments: Spot spay. Apply as foliar application. Spray regrowth after slashing.
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

---

Picloram 44.7 g/L + Aminopyralid 4.47 g/L (Vigilant II ®)
Rate: Undiluted
Comments: Prune all of the shoots horizontally at the rhizome. Apply a 3–5 mm layer of gel across the cut surface on the rhizome.
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

---

back to top

Biosecurity duty

The content provided here is for information purposes only and is taken from the NSW 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.

back to top

Reviewed 2024