Capeweed indicative of a larger problem

North East & Goulburn-Murray Farmer

PASTURES covered in the striking yellow of capeweed are a reminder of a year of lower rainfall, and drought conditions that allowed this monoculture to thrive while other grasses and clovers failed to prosper.

Arctotheca calendula or capeweed is native to South Africa, but is naturalised throughout the temperate half of Australia, and many parts of the world including Europe, New Zealand and south-western USA.

A member of the sunflower family the herb is deemed a noxious weed in parts of the world, however, capeweed in Australia is not considered a significant threat and is awarded low priority in weed management schemes.

It is a common weed of habitation and though increasingly becoming a problem in natural areas posing a threat to the integrity of plant communities, it is classified as merely an environmental weed in Victoria and treated accordingly.

“There are far more significant priorities to be dealt with than capeweed,” said Neil Devanny, chairperson of the Gecko ClaN, a community Landcare Network which supports 19 Landcare groups stretching from Yarrawonga to the Strathbogie Ranges to Nagambie.

Based in Euroa, Mr Devanny wears numerous hats, being not only chairperson of the Gecko ClaN but also chairperson of the Granites Creek Landcare Network and Gooram Valley Landcare, and among other things is a board member of the Victorian Rabbit Action Network.

He is thoroughly versed in issues pertaining to pest plant and animal control, and believes capeweed to be more indicative of a larger problem relating to sustainable agriculture and biodiversity.

“Capeweed is in your face, but it’s more a distraction from the real issues that are around,” Mr Devanny said.

“It’s not high priority, it’s a pasture weed.

“There are much more problematic weeds like blackberry, St John’s wort, prairie ground cherry, various other classified weeds.

“Capeweed is like Paterson’s curse – it’s a waste of money to have government funding thrown at it.

“It falls into the category of land management by individual landowners.”

Capeweed is a visual representation of a more significant issue with the pasture, be it soil fertility, overstocking or understocking, poor grazing management or problems with introduced pest species destroying or inhibiting native grass and pasture growth.

“If you over-graze you have capeweed,” Mr Devanny said.

“It’s up to land managers to manage their land in a way that minimises its impact.

“You are never going to get rid of it, so it’s a matter of controlling it.

“Just the same as every other pest plant and animal, you’ll never be able to eradicate them all, the best thing you can do is control.

“And of course control is going to be more or less effective reliant on factors like seasonal conditions.

“This year is particularly bad for capeweed but this is largely due to the nature of the season.”

An autumn with lower than average rainfall allows this broadleaf weed to germinate and then dominate the landscape, growing rapidly and smothering companion plants.

With the weeds keeping pace with the more productive pasture species, capeweed has dominated paddocks in the region, and provided a significant challenge for landholders.

The challenge lies in pasture management and pest and weed control.

“Rabbits can often be the cause of capeweed in areas, as they over-graze, causing other plants not to grow, while the capeweed flourishes, being a vigorous and robust annual,” Mr Devanny said.

Rabbits also transfer the seed in their faeces, with viable seeds passing through their gut.

With pest and weed management being Mr Devanny’s main focus, rabbit control is a primary consideration.

Matthew Vasey, farm manager for Dueran Pastoral Company, a 2000 acre sheep and cattle station 10 kilometres north of Mansfield, also believes in best management practice for his pasture.

“In regards to capeweed we’re not experiencing too big a problem, however, this is directly reflective of our pasture management program,” Mr Vasey said.

“We don’t over-graze pastures in summer to ensure ground cover is maintained.

“We use containment paddocks to protect pasture and rotationally graze the stock.

“And then we spray with MCPA in winter, and make it a priority to constantly renovate pasture to ensure good plant density.”

This long term approach to managing capeweed by establishing a dense competitive pasture seems to be paying dividends with the majority of Dueran’s accessible paddocks relatively capeweed free.

“Where we can’t drag the equipment – the spray units and the seed drills – capeweed is the predominant plant,” Mr Vasey said.

“But where we can apply the above treatments, we don’t have a capeweed issue.”

Employing a combination of good grazing management and avoiding over-stocking, while replenishing the bioculture and retaining vegetative cover during drier months, has seen this opportunistic pasture weed fail to establish itself at Dueran.

As capeweed prefers soil high in nitrates, and as a result is often found on sheep properties, Mr Vasey’s achievement is not to be underrated.

And with capeweed reducing crop yields for cereal and grain farmers, and leaving landowners short on fodder in the summer months, it may only be an environmental weed, but it is a serious consideration for farmers and the viability of their enterprise.

More farming news and stories can be read in the November, 2019 print edition of North East & Goulburn-Murray Farmer or click here to access digital editions.