Montbretia (Crocosmia x crocosmiiflora)

Montbretia is a vigorously growing bulbous plant. It is considered an invasive weed of environmental areas.


How does this weed affect you?

Montbretia grows in dense clumps and is capable of adapting to a variety of conditions. It out-competes native plants, particularly in native bushland and riparian areas. The biodiversity of ecosystems can be significantly affected by an infestation of montbretia. Dense growth of this plant along riparian areas can lead to creek bank erosion and sedimentation.

Montbretia can sometimes still be found for sale at local fetes, nurseries and markets.

What does it look like?

Montbretia is a perennial herb, usually growing to about 60 cm tall, but sometimes reaching up to 100 cm in height. The above-ground foliage is short-lived, and grows back each year from underground 'bulbs' and creeping stems (i.e. rhizomes). 

The green stems are long and strap-like. They are 30-80 cm long, 1-2 cm wide and are mostly clustered near the base of the plant. There are usually only about 6-12 leaves produced by each individual 'bulb'. The leaves are soft, and sometime droop towards the ground. They are hairless with entire margins and pointed tips.

The flowering stem of montbretia is 15-30cm long and zigzagged.

The trumpet shaped flowers are yellow to orange-red (usually orange-red with yellow centres).  The petals are 3-4 cm long and 2-5 cm wide. They have three stamens and a style that splits into three short branches near its tip. Flowering occurs mostly during summer and autumn, but also during spring in warmer climates.

The fruit are capsules (5-10 mm long) that turn from green to brown, and become shrivelled, as they mature. Seeds are usually not produced, but when present they are brown or reddish-brown in colour and flattened or triangular in shape (about 3 mm long and 1-2 mm wide).

Where is it found?

A horticultural hybrid plant, developed in France for ornamental purposes. It is the result of the intentional cross between the plants Crocosmia aurea and Crocosmia pottsii, both of which originated from South Africa.

Montbretia is located in all states of Australia, with the exception of the Northern Territory. It is most prevalent close to highly populated city and coastal areas. It is likely that spread has occurred from inappropriate dumping of garden waste.

In NSW, Montbretia is present at various locations along the eastern coast. Isolated infestations occur in the Tablelands regions and on Lord Howe Island. It is of particular concern in the Manly and Blue Mountains areas near Sydney.  

How does it spread?

Montbretia mostly spreads from underground runners and bulbs. Each plant can produce up to 14 new bulbs annually. These bulbs break off from the parent plant and begin to produce their own root network. This increases the size and density of an infestation. Bulbs can be transported to new locations by dumped garden waste, water and movement of contaminated soil.


Flowering occurs during summer and autumn. The leaves and flowers die back in autumn after producing seeds. Foliage begins to grow from the bulbs in spring. 

What type of environment does it grow in?

A weed of temperate and sub-tropical environments. It inhabits wetter grasslands, open woodlands, pastures, waterways, gardens, roadsides, waste areas, disturbed sites and railway enclosures.


Department of Employment, Economic Development and Innovation (2011) Montbretia: Crocosmia x crocosmiiflora, Queensland Government. Available at /03030800-0b07-490a-8d04-0605030c0f01/media/Html/Crocosmia_x_crocosmiiflora.htm. Accessed August 2014.

Hosking JR, Sainty GR, Jacobs SWL & Dellow JJ (in prep) The Australian WeedBOOK.

James, TA and Brown, EA (2014) Crocosmia x crocosmiiflora (Lemoine ex Burb. & Dean) N.E.Br., in PlantNET - The Plant Information Network System of The Royal Botanic Gardens and Domain Trust, Sydney, Australia. Available at Accessed August 2014.

Richardson FJ, Richardson RG and Shepherd RCH (2011) Weeds of the south-east: an identification guide for Australia. RG and FJ Richardson, Meredith, Victoria.

Weeds of Blue Mountains Bushland (2014) Montbretia: Crocosmia x crocosmiiflora. Available at: Accessed August 2014.

More information

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The bulbous nature of montbretia makes physical control difficult. Small infestations or individual plants may be manually dug up from the ground. All root material and bulbs should be removed.

Herbicide control

Foliar application of a registered herbicide during flowering can have some success. Best results are usually obtained using a wiper wand application over the foliage between flowering and fruiting.

Monitor control efforts and repeat treatments as necessary.

Herbicide options

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

See Using herbicides for more information.

PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Various products)
Rate: 1.0 L in 50 L of water
Comments: Spray between flowering and fruiting.
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: 1 part glyphosate per 1 part water
Comments: Weed wand application.
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
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 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.

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

Reviewed 2014