Yesterday, I took a few pictures in the vineyards at the Horticulture Research Center near Victoria, MN. We are well behind schedule for fruit ripening – which is expected with the late spring we experienced this year. There is some hope that we could catch-up somewhat if the rest of the summer remains warm and sunny.
However, years like this highlight the fact that selecting the right grape variety is crucial if you want to plant a vineyard at the extremes of where they will ripen. The following three pictures were all taken on July 1st. All three of these pictures come from different grape cultivars, although they are planted within steps of each other. In a year as cool as this year is turning out to be, it is easy to see that simply choosing the right grape variety to plant will have a huge impact on whether or not one will see those grapes ripen before the leaves fall off the vine!
The first two photos are from Vitis vinifera cultivars: Cabernet Sauvignon and Pinot Gris. Even though they are the same species of grapevine, one can see that the Cabernet Sauvignon is about 10 days behind the Pinot Gris in berry development. This is one point in the vine growth where this lag can be appreciated, thus these early stages of berry development (flowering and fruit set) are typically noted by winemakers in order to plan for harvest. For growers, it’s important to note these phenological stages in order to plan for disease management.
In V. vinifera, harvest occurs, on average, 120 days from flowering. This means that we should expect to harvest the Cabernet Sauvignon around Halloween this year. This may all be well and good if we were in California, but in Minnesota it could mean harvesting in snowshoes if the vines somehow make it through a frost by then. The Pinot Gris could possibly be ripe by mid-October. This is still not news to bet the farm on (literally speaking), but there is some hope. The average first frost in some areas of southern Minnesota is between October 11 -20th. If the weather stays warm and the leaves don’t start to drop, we might see some ripe fruit. Most of Minnesota will see a frost by the first week in October.
Now take a peek at the third photo. Marquette was bred as a cultivar that flowers early and ripens quickly. The cluster at the bottom of the page shows fruit that is past flowering, with many of the bunches starting to point downward on the vine and showing peppercorn-sized berries. Marquette seems to ripen more quickly than European grapevines, so we are likely looking at harvest sometime between mid-September and the beginning of October. However, even if we look at harvesting at the beginning of October it could still be a safe bet for most vineyards planted in Minnesota if we see typical weather for the rest of the year.