Clockweed (Oenothera curtiflora)

Also known as: butterfly plant, velvet weed

Clockweed is a herb up to 1 m that has clusters of small white or pink flowers. It is an environmental and agricultural weed that can host crop diseases.

This plant should not be sold in parts of NSW

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How does this weed affect you?

Clockweed:

invades grain crops
is a host for powdery mildew which can reduce crop yields
invades disturbed sites and competes with native plants.

What does it look like?

Clockweed is an annual herb up to 1 m tall.

Leaves are:

in a rosette at the base and alternate along the stems
oval with a pointed tip
2-12.5 cm long and 0.5-4 cm wide
wavy with minute teeth along the edges.

Flowers are:

white or light pink, fading to red or pink
small with 4 petals each up to 3 mm long
grow in spike-like clusters up to 40 cm long
open for less than one day
present in summer.

Fruit are:

a dry, ribbed, woody capsule with 3-4 seeds per fruit
oval
up to 1 cm long and 3 mm wide.

Seeds are:

reddish brown or tan
3.5 mm long and 1.25 mm wide.

Stems are:

upright
covered in soft hairs
woody at the base.

Roots:

The taproot is up to 3 cm in diameter.

Where is it found?

In NSW, most plants have been recorded in the Riverina region. Plants have been found in other parts of NSW from the North West to Murray region.

Clockweed is native to central Mexico and central USA.

What type of environment does it grow in?

Clockweed is drought tolerant. It grows:

on disturbed sites such as roadsides and cultivated fields
in bushland
along creeks and waterways
in urban areas, parks and gardens.

Maps and records

Recorded presence of Clockweed during property inspections (Map: Biosecurity Information System - Weeds, 2017-2026)
These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.

How does it spread?

Clockweed is an ornamental plant that has been planted in gardens.

By seed

Plants may each produce up to 1000 seeds. Seeds may be spread by wind or people dumping garden waste.

References

PlantNET (The NSW Plant Information Network System). Royal Botanic Gardens and Domain Trust, Sydney. Retrieved 6 February 2025 from: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Oenothera~curtiflora

Richardson, F.J., Richardson, R.G. and Shepherd, R.C.H. Weeds of the South-East- An identification guide for Australia. 3rd edn. R.G. and F.J. Richardson. Meredith, Australia.

Southwest Desert Flora (2017) Oenothera curtiflora, (Gaura parviflora) Velvet weed. Retrieved 6 February 2025 from: http://www.southwestdesertflora.com/WebsiteFolders/All_Species/Onagraceae/Oenothera%20curtiflora,%20Velvetweed.html

VicFlora (2024). Flora of Victoria, Royal Botanic Gardens Victoria Retrieved 6 February 2025 from: https://vicflora.rbg.vic.gov.au/flora/taxon/7e9bdf71-77a9-4594-a8e1-1e8d7e826378

Wagner, W. L. & Hoch, P. C. (2013). Onagraceae. Steyermark s flora of Missouri.

More information

Control

Physical removal

Seedlings and small plants can be hand pulled or chipped out using a hoe or other garden tool. Weeding will be easier in damp soil.

Chemical control

Spot spraying

Spray actively growing plants. Cover all of the foliage evenly.

Splatter gun

Splatter-guns use small amounts of concentrated herbicide. They spray large droplets that limit spray drift. They are useful for very dense infestations of weeds that are difficult to reach.

Weed wipers

Wipers or wands apply herbicide directly onto leaves. This can minimise damage to desirable plants near the weeds.

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 31/03/2030
Fluroxypyr 200 g/L (Various products)
Rate: 500 mL to 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 31/03/2030
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 31/03/2030
Glyphosate 360 g/L (Various products)
Rate: 200 mL per 10 L of 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 31/03/2030
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 31/03/2030
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 31/03/2030
Metsulfuron-methyl 600 g/kg (Various products)
Rate: 10 - 20 g per 100 L water plus non-ionic 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 31/03/2030
Metsulfuron-methyl 600 g/kg (Various products)
Rate: 10 g per 1 L of water plus non-ionic 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

2,4-D amine 700 g/L (Amicide Advance 700)
Rate: 285 mL in 100 L water
Comments: Spray at the rosette stage. For pastures, rights of way and industrial areas
Withholding period: Do not graze or cut for stock food for 7 days after application.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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.
Western	Regional Recommended Measure * (for Regional Priority - Eradication) Land managers should mitigate the risk of the plant being introduced to their land. Land managers should eradicate the plant from the land and keep the land free of the plant. A person should not deal with the plant, where dealings include but are not limited to buying, selling, growing, moving, carrying or releasing the plant. Notify local control authority if found.
	*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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

Reviewed 2024