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Vineyard CSI: How To Read Grape Leaves

In a sea of vines, ampelography can help growers tell which grape varieties are which. Credit: Copyright Tina Caputo

In a sea of vines, ampelography can help growers tell which grape varieties are which. Credit: Copyright Tina Caputo

Let’s say you bought some Cabernet Sauvignon vines from a local nursery to plant a vineyard. You decided on Cabernet because you determined that this particular grape variety would be best for your location because of its soil type, sun exposure and climate. But then a worrisome thought enters your head: What if the vines aren’t Cabernet Sauvignon after all, but some other less-suited variety? What if the nursery somehow got them mixed up with Sauvignon Blanc vines? That would be a mighty costly mistake.

You could pray, sweat and grind your teeth until the first grape clusters appear, and then wait some more until they change color and mature enough for you to figure out the vines’ true identity. Or, you could call an ampelographer.

Ampelography is a type of grapevine botany that uses the physical traits of grape leaves to identify varieties. Grape leaves vary quite a bit between varieties, so a skilled ampelographer can easily distinguish Cabernet Sauvignon from Cabernet Franc.

Expert ampelographer

Lucie Morton is a world-renowned ampelographer and vineyard consultant. Credit: Tina Caputo

Lucie Morton is a world-renowned ampelographer and vineyard consultant. Credit: Copyright 2017 Tina Caputo

In the world of ampelography, it would be hard to find a more renowned practitioner than Virginia-based vineyard consultant Lucie Morton, who travels around the country lending her expertise to grape growers and vintners.

Among Morton’s clients is one of California’s best Sauvignon Blanc producers, St. Supéry Estate Vineyards & Winery, which flew her out to the Napa Valley earlier this month to teach an ampelography class. I was lucky enough to participate in the workshop, and learn some tips from a master.

Before taking us into the vineyard, Morton explained the background and basics of vine identification. Lesson number one: “Looking at clusters is cheating.”

Mistaken identity

In the early days of the California wine industry, American vintners often brought back vine cuttings from Europe to plant in their vineyards. Sometimes, the varieties were not identified correctly, or were known in their native country by a different name than the one used by the rest of the world.

In the 1970s Morton began to discover that some vines planted in American vineyards were misidentified. For example, she said, in the Finger Lakes region of New York people used to say that the Chardonnay grown there tasted “Germanic,” due to the area’s cold climate. The real reason was because their “Chardonnay” was actually Riesling.

Up until the early 80s, nearly all of the “Pinot Blanc” planted in California was not Pinot Blanc but a French variety called Melon de Bourgogne. An ampelographer — Morton’s teacher, Pierre Galet — set the record straight. “It does not make you popular, pointing out other people’s mistakes,” Morton told the class.

Even so, her skills are in demand, even in the modern world of high-tech viticulture. Although DNA testing can identify varieties, Morton pointed out, it can’t distinguish between clones. Ampelography can. “There’s still practical value in this skill,” she said.

Anatomy of a grape leaf

According to Lucie Morton, the main characteristics that distinguish grape leaves include their lobes, petiolar sinuses and teeth. It's also important to look at the color and texture of the leaves. Credit: Copyright 2015 Tina Caputo

According to Lucie Morton, the main characteristics that distinguish grape leaves include their lobes, petiolar sinuses and teeth. It’s also important to look at the color and texture of the leaves. Credit: Copyright 2017 Tina Caputo

According to Morton, the main characteristics that distinguish grape leaves include:

Lobes: If you imagine the leaf as a hand, the lobes would be the individual fingers that extend outward. Some leaves have prominent lobes, other leaves are shield-shaped and have none.

Petiolar sinus: This is the empty space surrounding the stem of the leaf. Some sinuses are wide open, others are very narrow.

Teeth: These are the serrations on the outside edge of the leaf. Some are jagged and sharp, others are rounded.

It’s also important to look at the color and texture of the leaves.

In the vineyard

Students in Lucie Morton’s ampelography class examine vine leaves to identify the corresponding grape varieties. Credit: Copyright 2015 Tina Caputo

Students in Lucie Morton’s ampelography class examine vine leaves to identify the corresponding grape varieties. Credit: Copyright 2017 Tina Caputo

Providing each of us with a list of defining characteristics for several different grape varieties, Morton sent us out into St. Supery’s Dollarhide vineyard and challenged us to bring her back a leaf from each variety. If we got it wrong, we went back to try again.

Identifying the vines was more difficult than I expected. In a given vineyard row, not all of the leaves are identical, even among the same variety. Just when I would think I had a match, I’d notice that one of the distinguishing elements wasn’t quite right: The teeth were rounded instead of triangular or the surface was smooth instead of leathery. Each time I was sent back for another leaf, I came to respect Morton’s skill a little more.

Defining characteristics

Following are the characteristics of five of California’s most popular grape varieties:

Cabernet Sauvignon

Cabernet Sauvignon. Credit: Copyright 2015 Tina Caputo

Cabernet Sauvignon. Credit: Copyright 2017 Tina Caputo

Morton calls this leaf the “monkey face” or the “mask,” because when held with its tip facing up, it looks like it has eye and mouth holes. It has five lobes, rounded teeth and an open (or naked) petiolar sinus.

Chardonnay

Chardonnay. Credit: Copyright 2015 Tina Caputo

Chardonnay. Credit: Copyright 2017 Tina Caputo

This is a shield-shaped leaf, with shallow, sawblade-like teeth and an open petiolar sinus. The vine’s young shoots will have red nodes that are distinctive to Chardonnay.

Merlot

Merlot. Credit: Copyright 2015 Tina Caputo

Merlot. Credit: Copyright 2017 Tina Caputo

This leaf is longer than it is wide, with five prominent lobes, an open petiolar sinus and deep triangular teeth. It’s yellowish in color, with a waffled, leathery texture.

Sauvignon Blanc

Sauvignon Blanc. Credit: Copyright 2015 Tina Caputo

Sauvignon Blanc. Credit: Copyright 2017 Tina Caputo

This five-lobed leaf is green in color, with a wavy texture. It has a narrow, almost-closed petiolar sinus, a round shape and rounded teeth. The lobes have three prominent troughs that resemble spouts from a fountain.

Malbec

Malbec. Credit: Copyright 2015 Tina Caputo

Malbec. Credit: Copyright 2017 Tina Caputo

This leaf is a heart-shaped shield, with a relatively narrow petiolar sinus and shallow pointy teeth. It has a puffy, quilted look and a thick, leathery texture.

Main photo: In a sea of vines, ampelography can help growers tell which grape varieties are which. Credit: Copyright 2017 Tina Caputo


Zester Daily contributor Tina Caputo is a wine, food and lifestyle writer based in Northern California. Her stories have also appeared in the San Francisco Chronicle, Wine Review Online, VisitCalifornia.com and Sonoma magazine. 

16 COMMENTS
  • Rayray 10·13·15

    Hello Lucie,

    Thanks for the documentation. I found some grape vines in my yard and I’m trying to figure out what variety they are. They leaf looks very similar to the one your holding in your hand. The caption of the picture says Anatomy of a grape leaf at the top left.

    Ray

  • RAYRAY 10·14·15

    Oops, I forgot to ask in my post what grape variety belongs to the leaf I mentioned. The very first picture.

    Ray

  • Tina 10·15·15

    Hi Ray,
    I didn’t ID the variety in my notes, so I forwarded the photo to Lucie. She said it’s Cabernet Franc.

    Tina

  • Rayray 10·15·15

    Thank you so much Tina. Would you or happen to know someone that could tell me how I would get a DNA test on my Grapes/leaf? I thought that my grapes may be a variety called Prieto Picudo. and its scientific name, Vitis Vinifera. These vines in question have been in my moms yard for about 40 years. and never have been watered. they have been surviving by and under ground spring. Just last year when I moved home to take care of my mom, due to onset dementia, I was cleaning the back yard and came across them, buried in the weeds. I tasted them, and wow! They were sweet! I propped them up and this year decided to try to make some wine with them. I picked at 24brix but seem to be having a problem with the fermentation taking off. I hand picked and destemed each grape. That took me 9 hours for a 5 gallon bucket of grapes. My So2 levels I believe were to high and was killing the yeast. I figure, If I knew what the exact variety of grape I hade, It would help with my yeast selection and give me a better direction.

    Lost,
    Ray

    • G Morgan 9·12·17

      Add rehyrated yeast as soon as have have juice. Do Not add any SO2 until fermentation is complete.

  • Tina 10·16·15

    County farm advisors can be helpful. Where are you based?

  • Rayray 10·18·15

    I am based in Walnut Creek Ca.

  • JB 11·30·15

    Hello Lucie,
    I am in contact with Pierre Galet. Could you please contact me asap. Best, JB

  • Jim Anderson 4·6·16

    Need some assistance in identifying vines in Cyprus – can anyone assist?

  • Tina 4·6·16

    Hi Jim, Short of hiring an ampelographer to come and take a look, you could find a used copy of “A Practical Ampelography.” (It’s out of print now, but you can find it sometimes on Amazon or Ebay.) Or contact the ag department at a university in your area.

  • Uy 5·30·16

    Hi Lucie/Tina. I found some grapes in a recently purchased house. It looks like Chardonnay from the pictures above. The house is in Modesto, CA. I was wondering if someone could help me identify them. I have pictures but I am unable to attach it here.

  • Leslie Trail 6·26·16

    I have 4 grape vines and have all but 1 identified. I have Green grape (tight bunches, green with no blushing, big seeds and powdery white on the outside of the grape. Also, very late to sweeten.) the leaf looks like several red wine grapes! My leaf looks like the one that is used to describe the anatomy of a grape leaf, though slightly darker. Any ideas?

    • G Morgan 9·12·17

      The powder white is likely botrytis, a common fungi that likes your grapes as much as you do.

  • Becky 6·30·16

    We just moved into our new home and we have multiple grape vines growing. How can I tell if they are good to eat and what kind they are? I have no idea how to care for them properly.

  • kipper 2·9·17

    Hello Tina, thank you for the documentation , i have 2 new cultivars of grape vine ;my brother bought them to me but there’s no tag to identify what variety they are , so can you please help me to id them? but i don’t know where to send the pictures .

  • Jeanette 10·6·17

    I have a grape vine growing at my home I bought. Leaves are similar to the Malbec & Chardonnay very small purple grapes & inside never seem to get very firm.

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