How To Manage It?
Best practice management
Control of Bridal Creeper (Asparagus asparagoides) is possible by chemical, mechanical means and biological control. However, when mature flowering plants and rhizomes (underground growing points) are removed seedling may germinate from the soil seed bank and follow-up is critical. Integrated control methods combining techniques, with long term follow-up is advised for success. Preventing spread to new areas by animals is difficult, so preventing seed set is important and the best form of control. When controlling Bridal Creeper (Asparagus asparagoides) the underground rhizome, need to be removed or comprehensively killed as re-growth can occur. Large plants with extensive root systems and underground rhizomes can and will survive herbicide application as some rhizomes are not killed and follow-up may be required.
Chemical control: Herbicides have been the most effective method of control. However, because Bridal Creeper often grows in areas of native vegetation, it is particularly important to avoid contact with desirable plants or soil near tree root zones. Isolated plants can be treated with a recommended herbicide applied by spot spraying. As infestations become larger, a strategically staged approach for removal is advisable to ensure that treated areas are not re-infested (CRC 2003). In citrus and avocado orchards it is difficult to spray Bridal Creeper entwined in the leaves of trees. Pruning lower limbs to provide access underneath trees, a practice known as 'skirting', enables spot spraying with a recommended herbicide. Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au .
Non-chemical control: Physical control: Physical removal is not effective unless all the rhizomes are dug up and destroyed. This may be possible for new, small infestations or as a follow-up after several years of herbicide control of a larger infestation. Slashing the stems and leaves may prevent fruit production and slowly deplete root reserves but it will not eradicate an infestation (CRC 2003). Small infestations can be controlled by hand pulling where practical.
Hand pulling can only be used for small plants and infestation. The rhizomes (main growing points at the top of the soil where the stem emerge) should be removed when hand pulling. If the plant breaks leaving any or all the rhizome, plants will immediately regrow if conditions allow.
Mechanical control: However, for large dense infestations where little to no native plants remain, mechanical removal of above ground parts parts may help.
Competition and management: Grazing can provide some control of Bridal Creeper. Tamar Wallabies on Garden Island in Western Australia have successfully kept it at low levels there, and sheep grazing may be an option to control it under trees in remnant vegetation, woodlots and shelterbelts (CRC 2003).
Disposal: When removing material off-site, rhizomes can regrow and re-shoot if not killed. Any rhizomes that come in to contact with the ground, on or off site, will re-shoot. Material can be composted or solarised and the same methods should be used for the fruits containing seeds, as these can germinate and grow in to new plants. If the plant is being removed from gardens, dispose of it through local government kerbside collection or tip facilities. Fruiting shoot material should be bagged immediately to avoid it being dropped or dispersed by birds. Root material (which can survive being dried for long periods) and seeds should not be composted or mulched (CRC 2003).
Fire: Fire can also be useful in reducing above ground biomass of larger infestations. In winter-rainfall areas, Bridal Creeper often emerges before the first autumn rains so herbicides may be applied before post-fire regeneration of native vegetation. As well as improving the effectiveness of herbicide application, fire may help to destroy Bridal Creeper seed and the dense tuber mat. However, use of fire requires permission from government authorities and its frequent use may endanger the survival of many native plant populations (CRC 2003).
Fires in late summer and early autumn can remove all under-storey vegetation and improve access for later spraying. If fire is used, regrowth should be treated carefully with herbicide to limit above-ground growth and further reduce the stored root reserves. Infestations should be monitored regularly and over several years because of the probability of regrowth from remnants of the root system. Regularly check for new incursions, carefully removing them or treating them with herbicide, as necessary. For new or small infestations hand digging of roots may be an appropriate follow-up technique (CRC 2003).
Biological control: Effective treatment of Bridal Creeper with herbicides or manual removal is expensive and labour intensive. These control methods are not feasible in many areas because of the size and inaccessibility of infestations. Biological control is viewed as a preferred management option for Bridal Creeper infestations of this type (Wills 1999). There are three biological control agents that have been released in Australia. However, it will take many years for the biological control agents to reduce the density of Bridal Creeper due to the huge reserves stored underground in tubers (CRC 2003). An effective biological control agent on Bridal Creeper is the rust (Puccinia myrsiphyllii), that attacks leaves and stems that can have a major impact on the levels of reserves in the tubers, but the rust is not effective on the Wester Cape Form. There is also a leafhopper, a sap sucking insect that feeds on the photosynthetic cells causing them to turn white, and a leaf beetle that feeds exclusivly on the young expanding new tissues of leaves and shoot tips therefore reducing biomass and fruit production.
For further information see the Asparagus Weeds Best Practice Management Manual (available at https://www.environment.nsw.gov.au/-/media/OEH/Corporate-Site/Documents/Animals-and-plants/Pests-and-weeds/asparagus-weeds-management-manual-130486.pdf ).
Does it have a biological control agent?
YES. Three biocontrol agents released: an undescribed Erythroneurini leafhopper, a rust fungus (Puccinia myrsiphylli), and a leaf beetle (Crioceris sp.) (Harvey, et al 2023).
When does it grow? (lifecycle/growth calendar)
Seeds germinate in autumn and winter in leaf litter and at soil depths of up to 100 mm. Buried seed that does not germinate rots within two years, while seeds on the soil surface may be viable for at least three years. Compared to many other weeds, Bridal Creeper has a short-lived seedbank (CRC 2003). Bridal Creeper plants take at least three years to reach flowering size, the flowers appearing along the length of the shoots in August and September (CRC 2003). Shoots of established Bridal Creeper typically emerge from the soil in autumn but earlier emergence can occur in years of high summer rainfall.
The green berries turn red in late spring to early summer (CRC 2003). There can be large differences in fruit production between years and sites. Early autumn rains allow a longer growing season, which favours high fruit production. The amount of fruit set is significantly greater where shoots are able to grow vertically by climbing up shrubs and trees, and less where the plants are heavily shaded, suffer water stress or where there is a high level of competition between shoots (i.e. older, dense infestations) (CRC 2003).
Shoots (above ground stems and leaves) may be present year round in warmer areas which normally have summer rains or are under irrigation. In cooler areas above ground growth dies back in late spring – early summer as temperatures rise and soils become dry, leaves turn yellow and fall and stems die back in (CRC 2003).