Bitou bush (Chrysanthemoides monilifera subsp. rotundata)

Bitou bush is a spreading woody shrub with succulent stems, often prostrate on the ground. It primarily invades coastal dune systems.

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How does this weed affect you?

Bitou bush affects native plants mainly through competition, its high growth rate and, possibly, by releasing chemical inhibitors. Dense stands of bitou bush exclude other indigenous plants leading to decreasing floral biodiversity and, consequently, changes in faunal diversity. Stands of bitou bush also reduce the aesthetic appeal of natural environments and reduce recreational access to beaches and along walking trails.

In 1999, bitou bush was listed as a Key Threatening Process to Biodiversity in NSW and as a Weed of National Significance. No species is known to have become extinct as a result of bitou bush invasion but its distribution does overlap with those of some rare and endangered plant species, notably Pimelea spicata, Zieria prostrata, Cynanchum elegans and Thesium australe. Bitou bush displaces the dominant plants in communities it invades, for instance Acacia sophorae on coastal dunes, and leads to a decline in floral biodiversity, as well as changes in the diversity of birds, indigenous mammals and ground-dwelling insects. Stands of bitou bush may also foster sites that harbour pest animals, such as foxes and introduced birds, which feed on and disperse the seeds or shelter under bitou bush canopies.

Where is it found?

Bitou bush is native to coastal regions of South Africa. The exact date and manner of introduction of bitou bush into Australia are unknown. The introduction probably was accidental through dumping of ballast by ships arriving from South Africa. Earliest herbarium records indicate an introduction to the Stockton area near Newcastle, NSW, in about 1908. From 1946-1968 bitou bush was planted deliberately along the NSW coast by the Soil Conservation Service of NSW to aid in erosion control and post-mining rehabilitation.

Bitou bush has invaded coastal habitats in south-eastern Queensland, NSW and Lord Howe Island. Bitou bush is particularly prevalent on the central and north coasts of NSW. A population was also planted and has persisted near Menindee in western NSW and a small population is present near Melbourne, Vic. The total area infested is estimated currently to be over 70 000 ha in Australia.

Maps and records

• Recorded presence of Bitou bush during property inspections (Map: Biosecurity Information System - Weeds, 2017-2024)
  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?

Bitou bush spreads primarily by seed. Germination appears to be promoted by fire, soil disturbance (eg. after bulldozing), and ingestion of seeds by birds and mammals. Seeds also appear to germinate better after a period of weathering and leaching in the soil. Unlike boneseed, mature plants of bitou bush may resprout after fire, slashing and herbicide application. The seeds ripen from June to September and most usually shrivel, dry and fall off or are taken by animals. Some seed can stay on the parent plant for up to a year.

Dispersal occurs primarily by animals such as birds and foxes eating seeds and passing them in faeces. This can spread seed over distances of kilometres. Some seeds may also be dispersed by ocean currents or through coastal creeks and waterways. Localised dispersal can occur through movement of sand blown by wind. Human-assisted dispersal was a factor in the initial spread of bitou bush via deliberate planting for early erosion-control programs. Seeds may be transmitted by tyre treads or soil adhering to vehicles and equipment. Seeds otherwise fall to the ground under the parent plants.

Mature plants may produce up to 48 000 seeds per plant per year. The soil seed bank usually consists of 2 000 to 5 000 seeds per square metre. The viability of seeds in the soil is variable but generally low: 2-30%. The maximum longevity of seeds is unknown but viability of most seeds is considerably reduced after 2-4 years. Dormancy mechanisms are not fully understood but it is likely that the fleshy cover surrounding the seed contains chemicals that inhibit germination and must be leached or decomposed away for germination to commence. Fire, exposure and soil disturbance appear to enhance germination.

What does it look like?

Bitou bush is a spreading woody shrub with succulent stems, often prostrate on the ground. it is typically 1-2 m tall and 2-6 m wide. Bitou bush develops a creeping habit under shade and may smother canopies up to 10 m in height.

Its leaves are bright green, succulent, oval in shape with a tapering base and irregular teeth along the edge, 3-8 cm long. Young growth is typically covered by a cottony down.

Mature plants produce lots of bright yellow daisy-like flowers with 11-13 'petals'. Fruits are green, becoming black when ripe and contain only a single seed. The seeds are egg-shaped, 5-7 mm long, fleshy externally with an internal hard bone-like shell which is dark brown to black when dry.

Bitou bush differs from boneseed by its sprawling growth habit (versus the erect habit of boneseed), rounder and less obviously toothed leaves, flowers with more 'petals' (11-13 for bitou bush versus 5-8 for boneseed) and egg-shaped ribbed seeds (versus round, smooth seeds for boneseed).

What type of environment does it grow in?

Bitou bush grows in a range of environments from open exposed dunes to shaded forests. It is tolerant of shade, salinity, strong wind, wind-blown sand, salt and water, drought, low nutrients and, to some extent, of disturbances such as fire. Bitou bush grows poorly in wet or swampy soils and has a low tolerance to frost.

Bitou bush primarily invades disturbed and undisturbed coastal ecosystems. A variety of ecosystem types have been invaded including sand dune heathlands and grasslands, headland heathlands and grasslands, coastal woodlands, coastal dry sclerophyll forests, and littoral rainforests. Mallee vegetation in western NSW has also been affected by bitou bush.

Acknowledgements

Author: J. Vranjic (2000)(CRC Weed Management Systems and CSIRO Plant Industry)

Technical review: Royce Holtkamp, Paul Weiss, Jennifer Carter, Andrew Leys, Samantha Olsen, Brett Pengilly, Craig Shephard, Jeff Thomas, Neale Watson, Lisa Wellman, Graham Harding, and Robin Adair.

Editing: Richard Groves and Kate Blood.

References

Holtkamp, R. (ed.) (1993). Proceedings of a national workshop on Chrysanthemoides monilifera. Port Macquarie, NSW, 28-30 April 1993. NSW National Parks and Wildlife Service, NSW Department of Agriculture, and NSW Department of Conservation and Land Management, Port Macquarie.

Holtkamp, R., Groves, R.H. and Corey, S. (eds.) (1997). Bitou bush workshop. Sydney, NSW, 3-4 Sept. 1997. NSW NPWS and CRC for Weed Management Systems, Canberra.

Love, A. and Dyason, R. (eds.) (1984). Bitou bush and boneseed Proceedings of a conference on Chrysanthemoides monilifera. Port Macquarie, NSW, 8-9 August 1984. NSW NPWS, and NSW Department of Agriculture, Port Macquarie.

Parsons WT and Cuthbertson EC (2001). Noxious weeds in Australia 2nd Edn, CSIRO Publishing, Collingwood.

Weiss, P.W., Adair, R.J. and Edwards, P.B. (1998). Chrysanthemoides monilifera (L.) T.Norl., in Panetta, F.D., Groves, R.H. and Shepherd, R.C.H. (eds.) The biology of Australian weeds. Volume 2. R.G. and F.J Richardson, Melbourne, pp. 49-61.

More information

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Control

Prevention

It is important to keep uninfested areas clear of bitou bush. Once an infestation is established, preventing its spread into surrounding areas should be a priority. This requires integrated management to reduce seed production and the control of undesirable dispersal vectors, notably foxes. The control of indigenous or introduced birds or other pest animals as dispersal vectors is usually not practicable. A gradual replacement of bitou bush by indigenous plants that produce the "normal" food supply of indigenous seed-feeding birds could help to reduce dispersal of weed seeds. The quarantining of an area to stop movement of seeds in sand on vehicles and equipment may be necessary. Raising awareness amongst recreational vehicle users particularly in coastal areas is advisable where this form of dispersal is a problem.

Integrated management

When treating bitou bush in a natural ecosystem, it is essential to consider its management in light of other management issues so that they can be integrated to get the best results. When using these guidelines, it is essential to realise their limitations and modify them in light of experience and local knowledge. Each situation should be considered individually. Weeds need to be treated as part of larger land and water management issues. If the weed occurs in small isolated infestations, removal to prevent expansion is advisable. Larger infestations require planning to efficiently reduce the population to an acceptable level. That level will be determined by the management objectives of the area and the resources available to tackle the problem.

Treatment techniques

There are a number of different treatment techniques that can be used to control bitou bush but it is often better to combine a number of techniques for the best results. 

Mechanical treatment:
Mature bitou bush plants can be slashed, whilst seedlings can be hand-pulled to remove the entire root system. Plants are liable to resprout after slashing alone, but applying herbicide to stems immediately after cutting should prevent regrowth. Mechanical techniques are laborious and impractical for infestations that are extensive or in areas that are difficult to access and may also cause soil disturbance and erosion problems, particularly when large roots are removed.

Herbicide information:
Herbicides registered for bitou bush can be applied in winter at low rates that effectively kill the weed, yet have minimal impacts on coastal vegetation. Herbicides can be applied from the air, from the ground or by a cut-and-paste method. Plants which are coated with dust or seaspray (eg. those close to tracks or the beach) could be less affected by herbicides. Glyphosate and metsulfuron methyl have been the herbicides most widely and successfully used against bitou bush. See Herbicide Options for details on herbicides and application rates. See below for Herbicide options.

Biological control:
Two insects that attack bitou bush in South Africa have been released and are very well established in Australia. These are the bitou tip moth (Comostolopsis germana) which destroys the growing tips, and the bitou seed fly (Mesoclanis polana) that destroys developing seeds. Both agents are now distributed along most of the range of bitou bush and, together, are reducing seed production of bitou bush. A leaf-roller moth (Tortix sp.) is also established. Leaf-feeding beetles (Chrysolina and Cassida spp.) also were released but have either not established or are only colonising slowly. Research is continuing into other South African insects and fungi that attack bitou bush.

Fire:
An intense fire kills most mature bitou bush plants although a small proportion of plants resprout. Fire also kills bitou bush seeds in the litter and topsoil and stimulates germination of seeds from lower in the soil profile. Fire, therefore, can be useful in reducing the large numbers of bitou bush seeds present in the soil but much depends on the intensity of the fire which is determined in part by fuel load, season and fire history. Fire can cause additional problems such as increased erosion potential, increased traffic and access by humans and pest animals, and further invasion by weeds. Note that permission of the land owners and a permit from the relevant State fire authority is generally required to authorise the use of fire and that the fire should be undertaken by properly trained and equipped personnel.

Grazing:
Cattle eat bitou bush. This limits the spread of bitou bush onto grazed properties adjacent to heavily infested areas. Management of bitou bush through grazing, however, usually is not practised on public lands because of problems associated with stock such as browsing of desirable indigenous species, erosion from stock movement, fouling of areas by dung and the spread of other undesirable weed species.

Management guidelines

The major objectives for integrated management schemes are to: remove existing weeds, run down the amount of weed seeds in the soil, reduce the opportunities for reinvasion by the same or other weeds, and rehabilitate and revegetate with desirable indigenous species. The nature of invasion by bitou bush means that these objectives should be long-term, as considerable time is required to properly apply some of the management techniques. A lack of appropriate follow-up will quickly lead to reinfestation of bitou bush.

The following guidelines are some general strategies to manage bitou bush in particular ecosystems.

Isolated plants or small infestations:
Ensure that you have correctly identified the bitou bush plant before removal. Isolated plants can be physically removed, preferably before they have seeded, or treated with herbicide such as glyphosate applied by spot-spraying. As infestations become larger, a strategically staged approach for removal is advisable to ensure that treated areas are not reinfested.

Large and extensive infestations in coastal heath, woodlands and grasslands on hind dunes:
A multi-stage spray-burn-spray strategy incorporating biocontrol agents is recommended as a general strategy. Most bitou bush sites or all now harbour at least one biocontrol agent. Spray large patches of bitou bush in winter with herbicide. This can be applied aerially or from the ground. Leave some areas unsprayed to allow biocontrol agents to persist and subsequently disperse from. Next, burn portions of sprayed patches. This should remove unsightly patches of dead bitou bush and stimulate the germination of both weed and certain indigenous species which are present in the soil. On the south coast of NSW, an autumn fire is best but on the north coast, a spring fire may be more appropriate. Monitor sites for bitou bush, biocontrol agents and indigenous plants. In particular, determine the extent of re-emergence of bitou bush, impact of biocontrol agents on bitou bush seedlings and any regeneration of desirable indigenous plants. Respray as necessary to control regrowth and bitou bush seedlings which have escaped damage by biocontrol agents. Again, leave some patches unsprayed to harbour biocontrol agents. The timing of the respray depends on the region but in general it is best to spray before seedlings start producing seeds but after they have grown sufficiently tall and self- thinned. The time for bitou seedlings to reach maturity is at least a year on the south coast but as short as six months on the north coast of NSW.

Note that the full implications of a biocontrol-spray-burn-spray strategy to coastal grasslands have not yet been determined but many such ecosystems are known to be fire-adapted. In areas where a large proportion of the remnant vegetation is known to be fire-sensitive, fire should not be adopted.

Large and extensive infestations on coastal foredunes:
Fire is not recommended for bitou bush in these areas because of the sensitive nature of this ecosystem to erosion. Instead, a combination of biocontrol-spraying-mechanical removal may be most appropriate. Follow-up spraying may need to be undertaken regularly, as noted above for the hind dunes.

Rainforests:
Fire is not recommended because of the sensitive nature of rainforest plants to burning. A combination of biocontrol, spot-spraying and mechanical removal may be most appropriate for infestations within the forest. The numbers of new weed seedlings in rainforests may be low, due mainly to poor flowering of bitou bush under heavy shade. Most seedlings probably will originate from external infestations. It is important, therefore, to give priority to managing healthy infestations of bitou bush in areas surrounding rainforests. Given the likelihood of scarce resources and the complexity of management issues, the following considerations should also be taken into account when adopting a strategy. Attention should focus on all weeds at a site as bitou bush is unlikely to be the only weed present. The possibility of new and more vigorous weeds filling the gaps left after removing bitou bush should be minimised. Many bush regenerators first manage the smallest weed infestations and gradually work towards larger infestations. Smaller infestations in which much of the indigenous vegetation is intact have a greater potential for natural restoration. Strategies will need to be modified to accommodate special requirements such as the management of endangered plant and animal species. For example, it is possible that bitou bush could provide shelter for certain indigenous fauna. In other cases, endangered indigenous plants may be particularly sensitive to management techniques (eg. Pimelea spicata is very sensitive to herbicides). Exercise judgement to address the specific management objectives additional to the control of bitou bush. It is impractical to aim for complete eradication of the weed. Instead, aim at minimising weed infestations to a level where it is easier and cheaper to manage. For instance, target specific sections of the weed population such as seedlings that have not yet reached flowering age in heavily disturbed sites, or only heavily flowering plants.

Disposal

The unsightly stands of dead bitou bush that occur after spraying can be eliminated by compacting, trampling or fire, in appropriate ecosystems. If allowed to stand, the dead canes help to deter undesirable traffic and afford some physical protection to dune environments until they eventually decompose. Small amounts of bitou bush removed by clearing or hand-pulling also can be left in place to decompose naturally but, if practical, seeds should be removed and incinerated.

Herbicide options

See Using herbicides for more information.

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PERMIT 12251 Expires 31/03/2026
Glyphosate 360 g/L (Various products)
Rate: 2 L /ha
Comments: Aerial boom spray applications. Refer to the critical use comments in the permit.
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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PERMIT 12251 Expires 31/03/2026
Metsulfuron-methyl 600 g/kg (Various products)
Rate: 20–30g /ha
Comments: Aerial boom spray applications. Refer to the critical use comments in the permit.
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

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2,4-D 300 g/L + Picloram 75 g/L (Tordon® 75-D)
Rate: 650 mL per 100 L of water
Comments: Spray to wet all foliage thoroughly. Treat at flowering to fruiting stage.
Withholding period: Do not graze or cut crops (except sugar cane 8 weeks) or pastures for stock food for 7 days after application.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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Glyphosate 360 g/L (Various products)
Rate: 5 or 10 mL per 1 L of water
Comments: Handgun or knapsack. Spray to wet all foliage. Apply at peak flowering to actively growing bushes during winter. Do not apply during periods of drought stress. Use the higher rate for plants over 1.5 m.
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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Glyphosate 360 g/L (Various products)
Rate: 1 part per 29 parts water or 1 part per 19 parts water
Comments: Gas gun / Splatter gun application. Use the higher rate on bushes over 1.5 m
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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Metsulfuron-methyl 300 g/kg + Aminopyralid 375 g/kg (Various products)
Rate: 20 g per 100 L of water (always add a Wetter 100 mL/100L)
Comments: Spray to thoroughly wet all foliage. Adjuvant: Wetter 1000g/L non-ionic alcohol alkoxylate (Titan Wetter 1000 or BS1000 or equivalent).
Withholding period: Pastures - Grazing for meat production or cutting for animal feed: Do not graze for 56 days after application. See label for further details
Herbicide group: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors) + 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: High/Moderate

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Metsulfuron-methyl 600 g/kg (Various products)
Rate: 1 g of herbicide per 1 L of water + 2 mL organosilicone penetrant per 1 L of water
Comments: Gas gun / Splatter gun application. Apply as close as possible to the flowering stage.
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

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Metsulfuron-methyl 600 g/kg (Various products)
Rate: 10 g per 100 L of water
Comments: Spray to the herbicide mixture to the point of run-off. Ensure all of the plant is covered.
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

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Metsulfuron-methyl 75 g/kg + Aminopyralid 93.7 g/kg (Di-Bak AM)
Rate: 1 capsule for every 10 cm of circumference
Comments: Capsule herbicide: See critical comments on the label for details on how to apply and seal the capsule into the sapwood of the tree trunk.
Withholding period: Nil
Herbicide group: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors) + 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: High/Moderate

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Picloram 44.7 g/L + Aminopyralid 4.47 g/L (Vigilant II ®)
Rate: Undiluted
Comments: Cut stump/stem injection application. Apply a 3–5 mm layer of gel for stems less than 20 mm. Apply 5 mm layer on stems above 20 mm .
Withholding period: Nil.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
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.
All of NSW	Prohibition on certain dealings Must not be imported into the state, sold, bartered, exchanged or offered for sale.
All of NSW The Bitou Bush Biosecurity Zone is established for all land within the State except land within 10 kilometres of the mean high water mark of the Pacific Ocean between Cape Byron in the north and Point Perpendicular in the south.	Biosecurity Zone Within the Biosecurity Zone this weed must be eradicated where practicable, or as much of the weed destroyed as practicable, and any remaining weed suppressed. The local control authority must be notified of any new infestations of this weed within the Biosecurity Zone
Hunter A Bitou Bush Biosecurity Zone is established for all land within the Hunter Local Land Services Region except land within 10 kilometres of the mean high water mark of the Pacific Ocean, which includes parts of: Lake Macquarie Local Government Area, MidCoast Local Government Area, Newcastle Local Government Area, Port Stephens Local Government Area.	Regional Recommended Measure* (for Regional Priority - Containment) Entire Hunter Local Land Services region: A person must not, import into the State or sell. Within the biosecurity zone: If the weed is part of a new infestation of the weed on the land, notify the local control authority for the land as soon as practicable. Eradicate the weed or, if that is not practicable, destroy as much of the weed as is practicable and suppress the spread of any remaining weed. Outside the biosecurity zone: Land managers should mitigate spread of the plant from their land. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
North Coast Biosecurity Zone, which includes: Lord Howe Island, The entire Kyogle Shire, Lismore City and Tweed Shire LGAs. Byron Shire LGA (all land north of Cape Byron and all land outside of 10 km from the Pacific Ocean). All land outside of 10km from the Pacific Ocean in the following LGAs: Ballina Shire, Bellingen Shire, Clarence Valley, Coffs Harbour, Kempsey Shire, Nambucca Shire, Port Macquarie-Hastings, Richmond Valley. The core infestation includes all land outside the biosecurity zone.	Regional Recommended Measure* (for Regional Priority - Containment) Entire North Coast Local Land Services region: A person must not, import into the State or sell. Within the Bitou Bush Biosecurity Zone: If the weed is part of a new infestation of the weed on the land, notify the local control authority for the land as soon as practicable. Eradicate the weed or, if that is not practicable, destroy as much of the weed as is practicable and suppress the spread of any remaining weed. The core infestation: Land managers should mitigate spread of the plant from their land. Land managers should reduce the impact of the plant on assets of high economic, environmental and/or social value.
	*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here

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Reviewed 2024