Vineyard Chronicles: Navigating the Art of Rootstock Selection for Exceptional Wines

In the intricate world of viticulture, the selection of rootstock is a pivotal decision that can significantly impact the health, productivity, and longevity of a vineyard. Rootstocks serve as the foundation for grapevines, influencing their growth, resistance to pests and diseases, and adaptability to various soil conditions. Choosing the right rootstock is a nuanced process that involves considering factors such as soil type, climate, grape variety, and desired vineyard outcomes. In this blog, we will embark on a journey through the fascinating realm of selecting rootstock for a vineyard and explore the intricacies that viticulturists navigate to cultivate thriving and resilient grapevines.

When developing a vineyard, one of the most important decisions a viticulturist has to make is the selection of rootstock to plant and if it is right for the site and conditions. Vineyard owners need to consider the site-specific properties of individual soils, the individual requirements of the rootstock, and the relationship between the two. When choosing a rootstock, there are a few factors the grape grower needs to consider: its resistance to phylloxera (a small, yellow, aphid-like insect that feeds on the roots, and sometimes the leaves, of grapevines), resistance to nematodes, and other factors such as environmental tolerance to drought, wetness, salinity, and lime. 

Pests

The first step grape growers need to take when selecting rootstock is determining which pests are present in the growing environment. Experts say this is especially true if the site was used as a vineyard previously. When growing Vitis vinifera grapes, rootstocks are mandatory throughout the U.S. due to the wide prevalence of phylloxera.

Sam Simpson, the co-owner of Good Harbor Vineyards, explains "rootstock is situationally selected for soil, vigor, or known issues in the soil that you would want to mitigate the risk, as some rotostocks are less likely to be susceptible to certain issues." In our vineyards, we typically use 3309, 101-14, and SO4.

Researchers at the Michigan State University (MSU) Extension explain that rootstocks with Vitis vinifera parentage should not be your first choice for your vineyards in Michigan because of the insufficient Phylloxera resistance. They recommend many rootstocks that European growers use due to their most critical and dominant abiotic and biotic stresses. 

In vineyards, the second-most observed pests are nematodes. These are microscopically small parasitic worms. Science shows that there are certain rootstocks that are more susceptible to nematode damage, so paying attention to your vineyard selection will be important to determine which type of rootstock has more potential to be successful.

Environment

No matter where the vineyard is located, every site brings a unique combination of conditions due to differences in soil chemistry, physical features, and climatic factors. This is especially true when finding rootstock to plant in a warm climate growing region versus a cool climate growing region.

As you have probably figured out, there is no single “universal” rootstock that is suited for all situations. Chances are, there will be some “fine tuning” that will need to be done before finding the right rootstock for each vineyard block.

According to the Western Agricultural Research Center at Montana State University, you will want to select more cold-hardy varieties if your site has cold winters with low temperatures. Researchers explain that most cold-hardy varieties are “own-rooted” - which means the vine is planted on their own roots. Today, most vines are planted on rootstock, which means they aren’t planted on their own roots but rather the vine is grafted onto the root of a different vine species.

Michigan grape growers should base their rootstock selection on developing improvements in vine cold-tolerance, as well as Phylloxera and nematode resistance in a short-cycle package with the potential of improving fruit quality at harvest in cool climate viticulture.

The process of selecting rootstock is a critical and nuanced decision for any viticulturist or farmer. By carefully considering factors such as soil compatibility, disease resistance, and growth characteristics, growers can optimize the health and productivity of their grapevines. It’s important to strike a balance between the desired traits of the scion and the rootstock to ensure a harmonious and fruitful partnership. Ultimately, a well-informed choice in rootstock sets the foundation for a thriving vineyard, offering the potential for bountiful harvests and long-term success in the world of viticulture.