DEADLY: Martindale Estate owner Marian Parker has lost five sheep to green cestrum growing around her property. Pictures: Dean OslandCATTLE and sheep are dying sudden and possibly painful deaths because of the rapid spread of a toxic weed in the Upper Hunter that started as a scented suburban garden plant.
Green cestrum, which kills animals’ liver cells and leaves them dead within hours of eating just a few leaves, was ‘‘probably the most toxic plant we have in the area’’, said Hunter Local Land Services district veterinarian Digby Rayward.
‘‘Usually we see it in cattle. We do a lot of post-mortems, and the only sample we really need if we suspect green cestrum is a little sample of liver.
‘‘It causes massive necrosis [death] of the cells of the liver. It can kill them within hours. Green cestrum is a huge problem.’’
Its continuing rapid spread across the region, particularly along waterways including the Hunter River, has led to the rapid death of an unknown number of animals, caused tension between property holders, and prompted state and local government authorities to issue warnings.
Green cestrum (Cestrum parqui) is a class 3 noxious weed under the NSW Noxious Weeds Act, and identified as a plant which must be ‘‘fully and continuously suppressed and destroyed’’.
It is toxic to animals, including cattle, sheep, horse, pigs and poultry, and to humans, according to the NSW Department of Primary Industries.
DEADLY: Sheep at Martindale Estate. Pictures: Dean Osland
Two Rivers winery owner Brett Keeping, of Denman, said green cestrum was a ‘‘tough problem to solve’’ because it was spread by birds, but also because fencing to protect waterways from erosion by cattle was a barrier to managing green cestrum growth.
‘‘I support the fencing, but the first place you find green cestrum is under a clump of trees and many areas of the river are inaccessible,’’ Mr Keeping said.
He was not aware of the toxicity of the plant until five years ago when the winery first ran some cattle.
‘‘You hear of people losing animals because of it. It’s a nasty weed. Back in the old days there used to be teams of people whose job was to help with weed management in this area, but now it’s all up to the farmers, and 99per cent of farmers I know are time-poor and cash-poor.’’
Martindale Estate owner Marian Parker, of Denman, has lost five sheep to green cestrum.
The sheep died rapidly after eating leaves off the plant.
‘‘Some of them, they appeared to have suffered for a little while, but most of the time it’s fairly rapid,’’ she said.
‘‘Councils should be doing more to publicise what a problem it is. It’s the established stuff that’s the big problem.’’
DEADLY: Green cestrum. Pictures: Dean Osland
Not all property owners were vigilant, she said. And heavy rains and flooding increased the plant’s spread.
‘‘When we get a fresh flood come down, the water brings the seed with it.’’
Under the NSW Noxious Weeds Act landowners have responsibility for controlling noxious weeds on their properties.
Green cestrum is related to Cestrum nocturnum, known as night jasmine, which is common in suburban gardens and spread by birds.
A Hunter Local Land Services spokesman said both plants were toxic, although only green cestrum was categorised as a noxious weed.
The spread of the highly scented night jasmine beyond suburban areas would be a concern, the spokesman said.
‘‘We’d prefer if people cut the fruit off after it flowers and bin it, to control the spread of seed by birds.’’