Weeds are opportunistic plants that take advantage of bare soil, moisture and nutrients to grow. Weeds can be a problem in vineyards when they compete with vines for soil moisture and nutrients, interrupt vineyard machinery and operations, harbour vine pests or disease, pose a fire risk or cause taints in wines.
More than 600 weeds have been collated by HerbiGuide – a company that provides information on weeds, pests and diseases in Australian crops, pastures and horticulture (http://www.herbiguide.com.au). Of these 600 weeds, the ones of significance to viticulture as identified by the AWRI, in interviews with over 20 growers across Australia, are listed below.
- Caltrop (Tribulus terrestris)
- Capeweed (Arctotheca calendula)
- Common sowthistle (Sonchus oleraceus)
- Couch (Cynodon dactylon)
- Fat hen (Chenopodium album)
- Gazanias (Gazania linearis)
- Innocent weed (Cenchrus species)
- Kikuyu grass (Pennisetum clandestinum)
- Mallow (Malva parviflora)
- Native geranium (Geranium solanderi)
- Paspalum (Paspalum dilatatum)
- Prairie grass (Bromus catharticus)
- Rhodes grass (Chloris virgata)
- Scotch thistle (Onopordum acanthium)
- Silver nightshade (Solanum elaeagnifolium)
- Skeleton weed (Chondrilla juncea)
- Soursob (Oxalis pes-caprae)
- Wild radish (Raphanus raphanistrum)
- Wireweed (Polygonum aviculare)