Limestone Hills Trufffles

Limestone Hills is a boutique truffière growing four different truffle types on its alkaline soil. Starting out as a “newby”, Gareth Renowden has developed his knowledge and the business, and is successfully supplying truffles to restaurants and food enthusiasts for around 8 months of the year, and showing the potential for New Zealand to produce more of this high value food.

Gareth and his family came to New Zealand in 1996. He met his wife Camille, a New Zealander, on a ski slope in Austria “a long time ago”. They lived and worked in London for many years before Camille persuaded Gareth and their two children to seek a new life in the country of her birth. So it was that they arrived in Canterbury in 1996 looking for somewhere to live and something to do. Gareth’s experience was in editing and publishing but the prospects for that weren’t particularly promising in Canterbury when the main publishers were in Auckland. He wanted something new.

That arrived in the form of a serendipitous encounter with a house advertisement that boasted 450 truffle oaks.

“A little light bulb went off in my head and I thought ‘wow that's interesting’. So I did some research that led me to the scientist who had started the truffle industry in New Zealand, Dr Ian Hall,” says Gareth.

“He told me what was happening in New Zealand and sent me up to the Waipara Valley to talk to one of the first people to grow truffles. There I learnt that a nearby property was for sale and, as luck would have it, it met all the criteria that we wanted in a home – an older farm house with trees and views of a river away from the main roads.”

The added bonus was that the Limestone Hills homestead was on soil that was ideal for growing truffles. Most truffle plantations in NZ are on soils that have been heavily limed to raise the pH to around 7.8 or higher, but the Limestone Hills soil is naturally alkaline.

“Truffle trees need shelter, water and protection from rabbits and other pests, so we started by digging holes and laying out the plantation, installing irrigation and subsequently putting up some wind netting,” says Gareth.

“More recently we have fenced out rabbits and pigs because both can do a lot of damage in truffle plantations.”

The main truffles that Gareth grows – Périgord black, and white Bianchetto – prefer an open woodland environment where the tree canopy doesn’t shade the ground completely. Consequently spacing of planted trees is important says Gareth.

“The first truffière to produce truffles in NZ was in Gisborne, and they followed the European recommended spacing but the trees grow four times faster here than they do in Europe and so they ended up having to thin out the plantation,” he says.

“We planted trees 3m apart in rows 8m apart, and it was probably a bit close so we are thinning as we go to let the sun through.

“For the Périgord black, white Bianchetto, and the Burgundy truffles the trees most widely used are the common English oak tree Quercus robur and the hazelnuts Corylus avellana. The evergreen oak Quercus ilex is also good because it stands up to drought and hot winds.   For white Bianchetto you can even use Pinus radiata”

The trees are germinated from seed and then inoculated with truffle fungus. Originally truffles were imported from Europe and Scandinavia but today much of the inoculum is of New Zealand origin.

“The basic principle is that you germinate the seedling tree in a sterile environment and as soon as it's big enough to pot on you introduce it to the truffle spores. Sometimes they dip them in a slurry of spores or they introduce the spores into the potting mix that the tree is going to be planted in,” says Gareth.

“Basically you want the spores close to the roots of a seedling tree. As the spores germinate they go looking for a partner tree and if they find the seedling and if the conditions are right and you've done your job properly you end up with an inoculated seedling. What we are trying to do is to set up a mycorrhizal relationship that occurs naturally in forests, a relationship between a plant and a fungus.”

Limestone Hills’ Périgord black truffle trees planted in 1997 yielded their first truffles after nine years and Gareth thought they had done quite well. Production was small and remained quite small for some time until the science of the truffle industry took a giant leap forward, says Gareth.

“European scientists decoded the genome of the Périgord black truffle and now we have a much better understanding of what's actually going on in the soil around our trees without having to dig holes everywhere to check all the roots.”

It was thought that truffle fungi reproduced vegetatively but the science has shown that sexual reproduction is necessary and that most of the fungi around trees are “female” while their male counterparts are dispersed in the soil. Truffles rely on being eaten by pigs, rats and other fauna to spread the male spores throughout the soil. To achieve that they have evolved to produce the characteristic smell that hungry animals including humans find irresistible.

These understandings allow growers to give male and female a better chance of meeting by putting inoculum in holes around trees and so potentially increase production. It may well be that seeding certain kinds of bacteria into the soil around truffle trees may also encourage truffle growth and perhaps improve their aromas and quality.

Limestone Hills may be a small boutique truffière but it is the only New Zealand grower that has four different species of truffle in production, says Gareth.

“Our largest plantation is the original 250 trees of Perigord black. We have two small blocks now of the Bianchetto white truffle and the Burgundy truffle. In the early 2000s I was lucky enough to get hold of trial quantities of both species and we found their first truffles in 2012,” he says.

“Now these two little blocks are really very productive they have really changed our business. We get 8-10kg of Burgundy truffles from about 100 square meters of ground and at about $1000 per kg that’s a good return so we have plans to plant more. It also means we have a truffle season that runs from January right through to early September.”

“New Zealand has some advantages over Europe when it comes to truffles – the growing season is longer and there are large areas in both Islands that have limestone soils and are suited to truffle tree plantations.”

“I have two main markets for my truffles – upmarket restaurants, and private clients who are keen foodies – but also I can sell my second grade truffles, as long as they are ripe, to nurseries to use as inoculum.”

“We also do truffle tours, so people visit and we go out with Rosie the beagle, visit the trees and they learn a little bit about truffles, they get to see truffles being harvested, they can buy some to take away if they if they wish and we usually send them off to one of the winery restaurants and in the valley.”

Gareth’s current truffle dog (Rosie the beagle) has become famous and has her own Facebook page. He has trained both Rosie and her predecessor Peg – in fact Peg won the first ever truffle dog championship.

“Rosie was finding truffles when she was about four or five months old but as with all dogs it's one thing to be able to find a truffle and another for it to be a good worker, and it’s not until they are about 2 years old that you can tell. Rosie has turned out to be a really good little working dog and I'm pretty confident that she's finding most if not all of the truffles that we have,” he says.

“We’re very we're blessed here in that we have the environment, the soil, and two of the best winery restaurants in New Zealand just down the road so they often have truffles from us or our neighbours on the menu. We are just one of about 20 producers in the Waipara and Waikari areas, and with them we will be supporting the fourth Canterbury Truffle Festival later this year.” The Truffle Festival celebrates the peak of the truffle season, from July 23 to August 14 in 2018.