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Boneseed and Bitou Bush | LC0181 |
Department of Primary Industries
Updated: August 2007
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Common and Scientific Names
Boneseed
Bitou bush
Chrysanthemoides monilifera ssp. monilifera
Chrysanthemoides monilifera ssp. rotundata
Origin and Distribution
Boneseed and bitou bush are native to Africa. Boneseed is restricted to south-western South Africa where it is found on hilly terrain. Bitou bush occurs in coastal vegetation extending from southern South Africa to southern Mozambique.
Boneseed was cultivated as a garden plant in Australia last century and most of the existing infestations are believed to be derived from garden escapes. Boneseed is widespread and densely established in several areas of Victoria, with major infestations in the You Yang Range, Mornington Peninsula and Lake Hindmarsh. Bitou bush was apparently introduced in the ballast of ships from South Africa. It was spread along the coast of New South Wales by deliberate planting to stabilise coastal sands and in beach mining revegetation programs and is now the dominant species along 20% of the coastline.
Bitou bush infestations have occurred within Victoria at Melbourne and Mallacoota and although these have been eradicated in recent times, further infestations can be expected in the future.
Description
Woody shrubs with fleshy fruit which dry to form a hard stone containing the seed.
Boneseed
Erect, much branched shrub or small tree to 6 m high, commonly 1 to 3 m.
- Stems - branching above ground level.
- Leaves - obovate to elliptic, 2-8 cm long, margins irregularly toothed, blades thin.
- Flowers - present July -December, yellow, 4 to 8 (commonly 5 or 6) ray florets (petals).
- Fruit - globular, 6 to 8 mm diameter, light brown when dry; seed usually falling in January or February.
Bitou Bush
Sprawling shrub, 2 to 3 m high but often taller if supported by other vegetation, 2 to 6 m wide.
- Stems - crown at or below ground level, stems spreading horizontally before ascending.
- Leaves - fleshy, broadly obovate, 3 to 6 cm long, margins usually entire (sometimes slightly toothed).
- Flowers - most of the year, yellow, 11 to 13 ray florets.
- Fruit - obovoid, 5-6 mm long, dark brown to black when dry; seed fall is greatest between June and September.
Biology
Seeds germinate throughout the year, but seedling survival and growth is highest during the autumn and winter period. Plants flower within 2 to 3 years in open areas, but after fire flowering can occur within 12 months. Boneseed flowers from July to December, whereas bitou bush flowers most months with a flowering peak from April to June. | Figure 1. Boneseed. Note the toothed leaf margins and
5-6 ray florets per inflorescence.
Figure 2. Bitou bush. Note the entire leaf margins and
11-13 ray florets per inflorescence. |
On most soils, seeds accumulate on the soil surface and within the litter layer, and because of their relatively large size only a small proportion become buried. On coastal sands, which are prone to disturbance, seed is more likely to be buried. Both subspecies have large and persistent soil seed banks (2,500 seeds per square metre for boneseed, 9,500 seeds per square metre for bitou bush).
The Problem
Boneseed and bitou bush are serious weeds of native vegetation and reduce the aesthetic and conservation qualities of bushland areas. Dense infestations virtually eliminate native understorey species and reduce the regeneration abilities of native trees and shrubs. Several coastal plant communities and a number of species are threatened with either depletion or extinction by the invasion of boneseed or bitou bush in eastern Australia. Negative effects on wildlife also occur as infestations restrict the movement of larger animals and displace essential food plants.
Dispersal
Birds, including starlings and blackbirds, are attracted to the fleshy fruits of boneseed and bitou bush and are responsible for dispersal of the seed. Foxes are also an important vector. During the fruiting period fox scats laden with seed are commonly seen in bushland areas. Other dispersal agents are cattle and ants, but these are of minor importance. Viable seeds can be spread by the movement of soil, particularly by quarrying or extraction activities, water, vehicles, shoes, tyres and clothing.
Management Program
Some control methods described in this note are only effective if used in combination with other control options as part of a long-term management program.
If used in isolation, these methods do not effectively destroy the plant, allowing it to re-shoot or continue to grow. Authorised officers from DPI or DSE may direct landowners to undertake specific control activities to ensure methods are used that are capable of destroying plants and preventing their spread.
Where directed to do so, landowners must use the method or methods as directed by the authorised officer. In most cases the landowner will be able to choose from a variety of options appropriate for use in their particular situation.
A number of control techniques are available for boneseed and bitou bush. Some may be more appropriate than others, depending on infestation characteristics. As with most weeds, successful control is likely to result from the incorporation of a range of control methods. Hand-pulling and herbicide applications are dependent on good access, and are suitable for small or isolated infestations. The integration of fire, which is capable of killing plants, and biological control, which has the potential to suppress the vigour of regenerating seedlings, offers the greatest prospect for control of large infestations. Revegetation of sites using appropriate local native species after the removal of boneseed and bitou bush is important in reducing the chances of re-invasion by these or other environmental weeds. | Figure 3. Boneseed infestation. |
Fire
Boneseed is highly sensitive to fire and is killed by low to moderate intensity burning. Soil stored seed is stimulated to germinate by fire and subsequent rainfall. Seedling growth is then rapid and dense stands of seedlings compete intensely with regenerating native plants. Bitou bush is less susceptible to fire than boneseed. About 30% of mature plants are capable of regrowing from basal stems. The removal of seedlings and surviving mature plants by herbicide treatment or hand-pulling prior to the first fruiting period following fire (i.e. 12-18 months post- fire) can result in effective control.
Hand Removal
Boneseed has a shallow, weakly developed root system and most plants are readily removed by hand-pulling. In contrast, only small to medium sized bitou bush can be hand-pulled because this subspecies has a well developed root system that penetrates deeply into the soil. Hand-pulling is a highly selective control technique and is most useful in areas where minimal non-target damage is required.
Large bushes can be cut down by hand and the cut stumps treated with herbicide. The cut material can be left on site, however if it is bearing seed it should be burned.
Chemical Control
The Australian Pesticides & Veterinary Medicine Authority (APVMA) is responsible for the assessment and registration of agricultural and veterinary chemicals in Australia. As chemical products are registered on a daily basis and renewal of these registrations are undertaken each financial year, there is much change in the registration status of products each year. The information is available from APVMA (external link).
The Chemical Standards Branch (CSB) of the Department of Primary Industries provides information on agricultural chemicals registered in Victoria and their uses. Enquiries will be referred through the Customer Service Centre on 136 186. Information can also be obtained by visiting the CSB website.
Under Victorian legislation there are controls on the use of agricultural chemicals. It is the responsibility of the user to be familiar with these controls. These responsibilities are outlined in Agriculture Note AG0520: “Responsible use and handling of farm chemicals”.
Farm chemicals are registered for specific uses. Each chemical has a ‘product label’, which documents the approved use and the approved rate of use within each State of Australia. This label is important in determining the appropriateness of chemical use.
Choose only products registered for use on boneseed and bitou bush in your particular situation. Read the product label carefully and follow all label instructions.
Your chemical retailers can provide information on registered chemical products that are available in their store. They can also supply a ‘material safety data sheet’ that outlines the health and safety issues associated with use of a product.
Legal use of some restricted chemicals requires the user to possess an Agricultural Chemical User Permit (ACUP). Other chemicals have restrictions on their use in Agricultural Chemical Control Areas (ACCAs).
Information on ACUPs, ACCAs and other chemical information can be found at the CSB website.
Use a product containing active constituents or combinations of active constitutents registered for use in Victoria to control boneseed or bitou bush in the particular situation in which you need to use chemical control, eg. in non-crop areas. Consult the product label for detailed information.
Biological Control
A program is underway to introduce a number of natural enemies of boneseed and bitou bush from South Africa. Seven biological control agents have been released in Australia, the bitou tip moth (Comostolopsis germana), the black boneseed leaf beetle (Chrysolina sp.), the blotched boneseed leaf beetle (Chrysolina picturata), the painted boneseed leaf beetle (Chrysolina oberprieleri), the bitou tortoise beetle (Cassida sp.), the bitou seed fly (Mesoclanis polana) and the lacy-winged seed fly (Mesoclanis magnipalpis).
The bitou tip moth is established on bitou bush in New South Wales where it has significantly reduced flower and seed production in some areas. Establishment has not been confirmed in Victoria, Tasmania and South Australia. The Chrysolina leaf beetles are defoliators with both adults and larvae attacking the leaves, flowers and stems of boneseed and to a lesser extent bitou bush. Although these beetles are destructive on Chrysanthemoides in South Africa, difficulties have been encountered establishing them in Australia due to high levels of predation. The bitou seed fly was first released on the NSW coast in spring 1996 and spread tens of kilometres in less than one year. It has caused significant damage to seed at release sites. The lacy winged seed fly was first released in Victoria in June 1998.
A range of other organisms are being evaluated as potential biological control agents including other Mesoclanis seed fly species, the highly destructive defoliating leaf roller moth Tortrix sp., the leaf buckle mite Aceria neseri and the rust fungus Aecidium osteospermi.
For more detailed information on biocontrol refer to Landcare Notes LC0135, LC0136, LC0137 and LC0154.
Further Advice
- Contact your local landcare or friends group for further assistance and advice.
- Call the DPI/DSE Customer Service Centre on 136 186.
- Contact your local DPI Pest Management Officer for advice on local programs.
- Visit the DPI website
- Weeds Australia (external link)
References
Holtkamp, R. (Ed.) (1993) Proceedings of a workshop on Chrysanthemoides monilifera. Port Macquarie 28-30 April, 1993. NSW Department of Conservation and Land Management , NSW Department of Agriculture, NSW National Parks Service.
Holtkamp, R., Groves, R.H. and Corey, S. (Eds.) (1998) Bitou Bush Workshop. Abstracts of a Workshop held at NSW National Parks and Wildlife Service North Head Conference Centre, Sydney, on 3-4 September 1997. Adelaide, Cooperative Research Centre for Weed Management Systems.
Love, A. and Dyason, R. (Eds.) (1985) Proceedings of 'Bitou Bush and Boneseed: A National conference on Chrysanthemoides monilifera', Port Macquarie, NSW, 8-9 August 1984. NSW National Parks Service and Department of Agriculture New South Wales.
Parsons, W.T. and Cuthbertson, E.G. (1992) Noxious Weeds of Australia. Melbourne, Inkata Press.
Weiss, P.W., Adair, R.J. and Edwards, P.B. (1998) Chrysanthemoides monilifera (L.) T. Norl. pp.49-61 in Panetta, F.D., Groves, R.H. and Shepherd, R.C.H., (Eds.) The Biology of Australian Weeds Volume 2. Melbourne, R.G. and F.J. Richardson.
Glossary
| Blade: | Section of leaf excluding stalk |
| Elliptic: | Longer than broad and tapered equally at both ends |
| Entire: | Of a margin free from irregularity |
| Obovate: | An elliptical shape with the upper half of leaf broader than lower half |
| Obovoid: | Similar to obovate but with broader width |
Acknowledgments
Drafted by Robin Adair, edited by Sue Darby. Updated by Ross Williamson, 1997, and Ian Faithfull, May 1998. Updated by Melanie Martin, DPI, October 2006. Chemical information supplied by Chemical Standards Branch August 2006. Updated by Adam Kay, DPI, August 2007.
The advice provided in this publication is intended as a source of information only. Always read the label before using any of the products mentioned. The State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.
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