Discussion Paper - Part A - Victorian Environmental Assessment ...

Figure 5.20 Part of the North East Catchment Management Authority program to remove willows fromthe banks of the Ovens River in northeastern Victoria.In the study area, Paterson’s curse (also known assalvation jane) is an annual or biennial herb native to theMediterranean region, with vivid purple flowers. It is aserious pasture weed that also invades native vegetationincluding lowland grassland and grassy woodland, drysclerophyll forest and riparian vegetation. It iswidespread and well-established in Victoria. Paterson’scurse is poisonous to livestock but used as a pollensource by apiarists. It has a rapid early growth rate andspreading rosette of leaves and thus competes withpasture plants and indigenous vegetation. Birds andwater disperse the seeds but movement of hay,especially during drought, is also an important means ofdispersal. Thus, feeding contaminated hay to cattle onpublic land will contribute to weed spread. Carefulmeasures to prevent its spread are integrated withherbicidal, physical and biological control techniques tosuppress this established weed (Faithfull & McLaren2004). Several biocontrol agents are established andcontinuing to spread.African boxthorn is native to the southern coast ofAfrica and was probably originally planted in Victoria asa hedge plant forming a barrier to domestic stock. It is adensely branched perennial spiny shrub growing toabout 5 m round with bright red berries. Boxthorninvades many habitat types and can form dense thickets,providing refuge to native and introduced animals. Theattractive berries are eaten by birds and foxes, whichspread the seed, and it will also readily shoot frombroken roots. Removal with a chainsaw and subsequentpainting of the stem with herbicide is the most effectivemethod of control although follow-up work is requiredto remove seedlings. In some instances, wherealternative accommodation is unavailable, this speciesprovides valuable habitat and protection from predatorsfor species such as small birds. In such circumstances,Figure 5.21 Arrowhead (Sagittaria), an aquaticweed found in natural waterways and irrigationchannels.any programs to remove plants should be integratedwith programs to concurrently restore native habitat.There are native plant look-alikes so, as with all weedcontrol activities, identification before control is important.Horehound is native to many locations includingsouthern and western Europe, western and central Asia,North Africa and is now widespread in southernAustralia. It is a perennial, spreading herb growing toabout 80 cm and its fruits are burrs that spread attachedto the fur and feathers of animals, via water, clothingand vehicle tyres. Horehound invades pastures as well asred gum woodland, mallee shrubland, lowland grassyand grassy woodlands, black box woodlands and opengrasslands particularly if the areas have previously beenovergrazed or disturbed (Weiss et al. 2000; Blood & CRCWeed Management Systems 2001).Discussion Paper79