Monday 8 October, 2012
Tamworth Regional Council Noxious Weeds Unit will start its annual program to prevent the spread of St John's wort this month.
The unit will undertake a series of inspections on properties across the region from October to February to ensure landowners are undertaking control measures on current infestations. It also has a schedule of roadside inspections and control operations.
St John's wort is a perennial plant, native to Europe, with bright yellow flowers in dense clusters at the ends of branches from late October to January. Its leaves and branches are always opposite one another on the stem. The leaves appear perforated when held up to the light.
'St John's wort is widely known in the community for its use as a herbal treatment for depression, but it has quite serious effects when eaten by livestock,' said Noxious Weeds Officer, Penne Brazel.
'Unfortunately the Tamworth region has numerous infestations of St John's wort because growing conditions are ideal with altitudes above 500 metres and more than 600mm of rainfall on average though the year.'
St John's wort contains hypercin which causes photosensitisation in sheep, cattle, horses and goats. The associated skin damage leads to weight loss, reduced productivity and, in extreme cases, death.
It can result in less wool production in sheep and less milk produced in sheep and cattle. There can be fewer live lambs and calves born and a reduced number of animals surviving to weaning. St John's wort also makes it likely that fewer ewes or cows wiIl be healthy enough to conceive. St John's wort competes with useful plants in pastures and large infestations can reduce property values.
Landowners who suspect they may have St John's wort on their property are asked to report it to Tamworth Regional Council by calling 6767 5555. Council's noxious weeds unit staff will then follow up on all reports of infestations.
Ms Brazel said the most cost-effective and practical control techniques for St John's wort vary depending on the scale of infestation and topography of the land.
'Ideally, members of the noxious weeds unit would like to inspect an affected property and then recommend the best strategy for eradication,' Ms Brazel said. 'Spot-spraying can be best for isolated infestations and this is best done when the St John's wort is in flower because it is most sensitive to herbicides at that time.'