Omega keen to crack the big time

They're not fully grown yet, but once they are, the trees on Omega Walnuts' Manjimup property will make up WA's biggest walnut plantation.

Set to come into production in two years' time, the 22,000 trees are expected to yield around 250 tonnes of nuts per annum in seven to 10 years.

As the only large-scale commercial walnut operation in the State, orchard manager Paddy Elphick said it had been a learning curve.

The orchard uses the variety Paradox as rootstock but, as Paddy explains, walnuts are not grown the same as other horticultural trees.

"You would expect a conventional orchard to be grown with rootstock cuttings that are cloned with known history and parentage," Paddy said.

"(Walnuts) are not grown like that. They are seeds that are grown, selected out with Paradox qualities and then they are grafted.

"Normally, you would take a cutting of the rootstock and then you would bud that with the bud of variety of say peach or apple, but in this case, it's a seedling.

"Within seedlings, you get genetic variation."

Typically, orchards would buy in already grafted trees from nursery, but at around $38 per tree landed, it's an expensive process.

Paddy said Omega aimed to be self-sufficient with replacing trees by grafting its own.

A line of Paradox seedlings was planted in September last year and budded in February before being dug up and planted in the orchard this winter to replace missing trees.

"What we will do is select healthy plants, take cuttings and bud them and then we will have what we believe will be the best rootstock with the best variety, instead of relying on a variation of seedlings," Paddy said.

"We've had a 92 per cent success rate so far with the buds, but we've got to prove it and grow them on yet."

While Manjimup's fertile soils and number of chilling hours are perfect for walnuts, there are still challenges when it comes to growing the trees commercially.

Strong south-easterly winds mean the trees have to be staked and managed to maintain a straight shape.

Disease is a concern, but it can be controlled with the correct management practices.

"There's only one disease above ground that bothers walnuts. It affects the fruit and is called walnut blight, which is a bacterium," Paddy said.

"It can't be cured, only prevented, so the management of that disease is critical. There's only one effective treatment and that's copper sulphate.

"The scary thing is that resistance to copper sulphate is showing up in some parts of the world."

Like any horticultural enterprise, there are challenges, but there are also huge opportunities in walnuts.

California has the largest slice of the walnut market and although there are more considerable walnut operations in the eastern states, Australia is still a net importer of the nut.

World demand for walnuts is growing at 4 per cent per annum and Australia's current production is valued at $725 million - up 50 per cent on five years ago.

"It seems at the moment demand in China is greater than California's ability to supply," Paddy said.

"The fact that China is starting to plant walnuts is of concern, but we are a little bit ahead and we may be able to establish a market. Californian walnuts are starting to be diverted to China and we would love to export as well, if the price is there."

There is also an opportunity to supply the domestic market.

"Walnuts in shell can't be bought in WA without it costing the importer a lot of money, because they must be fumigated with methyl bromide," Paddy said.

"That prohibits the import of walnuts in shell, although walnuts as kernel can be imported without any treatment.

"Initially, our aim would be to market locally - we would love for simplicity and ease of marketing to sell locally. The (domestic) market at this stage seems to be for in shell, but I think down the track it's going to be kernel.

"We've just imported a cracking line from France and … I think our market is probably going to be 80 per cent kernel and 20 per cent in shell, but it's too early to tell."