Tips for growing lesser-known wine grape varieties

Roger Gamache

Gamache planted his first Malbec in 2003 and has clones 9, 4, and 6. Vines are spaced nine feet between rows and five feet between vines in a north-south orientation on an east-facing slope. His soil has a caliche layer, and the site has medium heat units of around 3,000 growing degree-days.

“We’ve been just tickled with Malbec,” he said. “It’s not a vigorous grower on our shallow soil, which is one of the key ingredients to our site.”

He tried machine harvesting but says the skin on the red grape is too thin, and it almost made wine during the harvest process.

Andrews, who keeps detailed data on all of his varieties—from bloom and lag phase dates to thinning and leaf stripping dates to cluster weights and special concerns—added that Malbec has done well for them in their shallow site with vines spaced six feet apart and nine feet between rows.

They keep yields to around 3.75 tons per acre, remove leaves in the fruiting zone by hand and cluster thin, removing wings from cluster. He has Malbec trained to a bilateral cordon.

Barbera

Barbera is a red variety from Italy. Andrews has two blocks of Barbera, clones 2 and 15. Clone 2 is trained to a bilateral cordon; clone 15 is trained to a unilateral cordon.

The red variety has light skin and sunburns easily and is slightly susceptible to cold. He believes it does best on an east slope. He characterized it as being moderately vigorous.

The variety seems to have some bloom and fruit set issues that result in immature berries.

“With Barbera, we always clip the wings, which is a step that we don’t do in a lot of other varieties,” he said. In some years, he color thins the clusters. Average yield has been between 4.8 to 5.5 tons per acre.

Grenache

Mike Andrews

Grenache believed to be from Spain, is a high vigor, red variety.

“Grenache takes the most work of all my varieties,” said Andrews, adding that he has four blocks planted of clones 3 and a Tablas Creek Vineyards clone, all trained to a bilateral cordon. “Some of the clusters from the Tablas Creek clone are more than a pound in size,” he noted.

He recommends planting on east or north slopes, avoiding west slopes because Grenache is very sensitive to cold and sunburns easy. Clusters can have small and large berries, something that winemakers don’t particularly like.

Cluster wings must be removed, and for some winery customers, the bottom third of the cluster is also clipped off. He leaves extra buds at pruning because the variety usually has some sort of winter damage.

Grenache yields for Andrews vary, depending on the block and production targets. The lowest yields last year were 2.6 tons per acre; the highest were 4.1 tons per acre.

Mourvèdre

Mourvèdre is an upright growing red variety from France. Andrews has clones 4 and a Tablas Creek clone, all trained to a bilateral cordon. Two blocks are spaced nine feet by six feet and two are eight feet by six. He made the mistake of not leafing every Mourvèdre block last year, which created shading problems later in the season.

“Leafing can be done by hand or mechanically, but it is an important step and shouldn’t be skipped,” he said.

Clusters were first thinned in early June and were thinned again in two blocks, and a third time in one block. His yields last year were 3.9 to 4.8 tons per acre. “Mourvèdre is a large clustered variety and has a few more steps involved than others.”

Petit Verdot

Petit Verdot, another French red variety, has showed some susceptibility to cold but it is tolerant of sunburn. Petit Verdot is planted to three different densities at Coyote Canyon Vineyard and does well in all three densities (eight feet by three feet, nine feet by 3.7 feet, and nine feet by six feet). “It has a smaller cluster and requires more work to drop the wings,” he said.

In some years, color thinning is needed, but not last year. The variety also requires extra canopy management towards the end of the season. Yields have been around 4 tons per acre. “One year we were too stingy on water and found that the canopy didn’t recover quickly.”

Viognier

Viognier can be a heavy producer, which is why Gamache choose it for their shallow soils. His block is planted nine feet between rows, six feet between vines.

“It’s a beautiful white grape variety, but if you have too much canopy, it won’t ripen and just stays green,” he said. Moreover, Viognier also has a very short harvest window. “If you’re late by three days, it’s over the top and you’re too ripe.”

Roussanne

Roussanne is more tender than Viognier, says Gamache. Because the white Rhone variety sunburns easily, he leaves more canes on the west side for sunburn protection.

Also, clusters should be positioned on the cordon with sunburn protection in mind. His crew hand picks Roussanne to give him more control over fruit quality and uniformity. “Sometimes during harvest we’ll leave clusters on the vine if we don’t like what we see.”

Andrews, who has the Tablas Creek clone planted, has found Roussanne to be fairly cold tolerant and without fruit set issues. He, too, has found that the variety sunburns easily, so he avoids using a movable catch wire on the trellis.

Typical cluster sizes are around 0.36 to 0.45 pounds and the variety is picked early in the first half of September. Yields have been from 4.3 to 6.1 tons per acre.

Marsanne

Marsanne, another white Rhone varietal, has performed well for Andrews, though it has taken a while to get established. Andrews has Marsanne planted eight feet between rows, six feet between vines.

Row orientation is east-west. He thinks the long establishment time could be related to the site because it has poor quality soil and high pH. Marsanne yields have been around four tons per acre.

“On the plus side for this variety, we don’t have to clip wings and thin fruit, and we’ve never had any fruit set or sunburn problems.”