Weed Control Curious? Demos Show Where the Cuts Are Made, Experts Weigh In

A crowd of 50 wine industry professionals looking for the best way to mechanically remove under-vine weeds gathered on a hillside in Sonoma’s Dry Creek Valley at Michel‑Schlumberger Wine Estate in May to see a demo from four different manufacturers: Clemens, Pellenc, Fischer’s Twister and the Italian-made Gramegna.

Incoming vineyard manager and winemaker Natalie Winkler, an expert in organic viticulture, is converting the formerly conventionally farmed vineyard to organic. She’s already converted Salvestrin in Napa to organic farming and certification, including its historic Dr. Crane vineyard.

Now that she’s back working in Healdsburg, in her new job Winkler needs to buy weed-control equipment. She invited friends from Napa Green to broaden the invite list to the demo so dozens of locals could come have a look and see firsthand how each of the implements cut fresh spring weeds.

Fueled by donuts and coffee, the assembled group was very attentive, closely examining exactly how precisely the blades, plastic tubes and string whippers lash the juicy, young spring weeds.

Vintner and vineyard manager/winemaker Ames Morrison of nearby Ames Medlock winery came to look for equipment compatible with his regenerative no-till vineyard. He said his current but aging weed implement raises a lot of dust and has parts that wear out fast. He’s looking for an implement with a whipper, which would be gentler than tilling.

Others just want something that will get the job done.

Prices for the equipment at the demo ranged from $14,000 to $16,000 for the Gramegna, $18,000 to $35,000 for the Clemens (modular), $27,000 for the Pellenc under-vine system and $35,000 for the Fisher Tornado.

Vineyard Managers Use a Wide Variety of Solutions
Growers around the state were quick to say that under-vine weed control is not a one-size-fits-all equation.

In Napa, longtime vineyard management company head Mark Neal of Jack Neal & Sons says he has many different models. As to which one is best, he said, “It all depends on the methods or what type of terrain you have, the slope and the type of cover crop.”

On the company’s Instagram, a posted photo of a Pellenc under-vine cultivator says in the caption, “We love this thing!”

Over in Lodi at Vino Farms, the huge vineyard management company is now farming 900 acres organically. Vineyard manager Mike Hardester likes the popular Clemens equipment.

“We use the finger roller in conjunction with the weed knives,” he said. “The weed knives tend to move dirt away from the berm while cutting the weeds below the soil surface. After we run the weed knife, we wait a couple weeks or until we have new weed growth, then come back with the finger roller, which throws dirt back on to the berm. The finger roller has angled tines that move the dirt inwards toward the berm. The finger roller also can cover emerging weeds, suffocating them.”

On hillsides, the team uses the Spedo, he said. “We can connect under-vine flail mowers or a rotary cultivator, if we want, depending on if we want to mow or cultivate.”

In the Santa Cruz Mountains, longtime organic vineyard manager Prudy Foxx has run her vineyard management company since 1997 and farmed for 30-plus vineyards and wineries. She said she’s tried a lot of the implements but comes back to just two main favorites: the Clemens and Gramegna.

She has gotten rid of others that were ergonomically too difficult or ones that tore up the ground too much.

“You want to be somewhat gentle with your soils… especially as we become so aware of biological activity in the soil. So you don’t want to be ripping the soil apart a foot down or half a foot down,” Foxx said.

She also likes a handheld weeder that’s electric. “The only problem I’ve had with it is just teaching the guys to use it without over‑manhandling it because they tend to want to use it like a regular hoe and drag it back and forth. It’s called the Cultivion Alpha from Pellenc.

“It’s really nice for areas that don’t have tractors or have tight spacings or real small vineyards where they can’t afford the more expensive equipment.”

The Pellenc Sunflower, Foxx said, “actually looks like a sun. There’s another one that’s kind of got these weed fingers, it basically looks like a disc with fingers sticking out of it, like a little kid would draw a sun. It is made of a rubbery material, and so it doesn’t really go in and out between the vines. But when it hits the vine, it doesn’t hurt the vine. It just sort of keeps going. It just sort of whacks it, because it’s rubbery, and it just goes around and it just bends back and goes around. It doesn’t get stuck there. It’s not metal. And so that’s pretty good. That works well if you’re there early and often, and you get your weeds while they’re still really small. If you wait until they get big, it really doesn’t work well.”

A rare one on her list is the Rinieri. “That’s actually a really nice one because it fits on a three-point hitch. That’s an important feature because some of these little ones might not even require hydraulics. If you’re using it on a tractor, you want to be able to take it on and off easily. That ease of use is huge.

“The downside of it is that it’s behind you, so you’re constantly looking back behind you. So that’s an issue,” she added.

But one of her guys figured out a workaround. “He put a piece of pipe in front of the tractor that was flexible the same distance out that the back implement goes, and so basically he could see where the edge of the multi-clean was in the back by watching where the pipe was in the front. And it was flexible, so when it would hit the vines, it wouldn’t hurt anything. But he could see where he was without having to look back all the time. I thought that was super clever. So there’s these kind of hacks to try to make it easier on the person using the equipment.”

Nature-Based Options for Weed Control
An increasing number of wineries are renting sheep to graze in the vineyard before bud break, saving a few tractor passes and fertilizing the soil as well as inoculating it with sheep saliva.

In California’s Capay Valley, one tiny grower with a one-acre vineyard, Vitis Ovis, uses ducks year-round.

A cutting-edge, autonomous French-manufactured solution called TED from Naio is being used in France. The company demoed it at the FIRA USA show in Woodland, Calif. in October and plans to exhibit it again this fall at the next FIRA USA show.

The Long View
Santa Rosa-based PellencUSA dealer John Felice, a vineyard-equipment industry veteran, said trends come and go in weed control. He said sustainable winegrowing killed the market for what once was the most popular organic weed-control implement, the Pellenc Sunflower, which Pellenc no longer makes.

“Weeding and cultivating movement was really strong during the organic season,” Felice said, “back in the early 2000s. And then everything changed to sustainable, and they told people they could spray it under the vine again. And about 2012 or 2013, that eliminated the Sunflower because our factory wasn’t going to produce it, because it wasn’t being sold, because everybody was spraying under the vine again.

“We went from selling 50 of those things a year to selling one because everybody could cover a lot more ground spraying.

“But then there was a study done, and the under-vine spraying found traces of the chemicals [glyphosate] in the actual finished product of the wine. So that brought back the emergence of under-vine cultivation [and herbicide-free vineyards] and mowing under the vine.”

Today, he said, people still clamor for the Sunflower, citing a recent demo in Mendocino County. “You go up into the Anderson Valley where there’s a lot of different hillsides… We did a show up, it was just us and Clemens. And everybody there was asking for the Sunflower. ‘How do we get Sunflowers? Right? We love our Sunflowers.’

“They also have our under-the-vine cultivator,” Felice continued. “Some people have the Clemens under the vine. They all know what works. But then you try to put a knife in the ground and the ground starts going away because there’s a slope. If you have limited adjustment for that slope, you can only go so far. With the Sunflower, it just kind of lays on the ground, hugs the ground and centers itself on the row.

“I just sold one of our new under-vine cultivating tools to a vineyard here in Sonoma, and that guy has two used Sunflowers for sale. Someone would have to buy them and put some money into them, but if anybody’s interested, they’re around.”

Felice said he’s also appealed to the higher-ups at Pellenc in France to bring back the Sunflower. “This is what people want. We need to bring it back,” Felice said.