Rootstock is the rooted lower portion of a grafted grapevine. It supports the upper fruiting variety, known as the scion, and is selected for traits such as resistance to phylloxera, adaptation to soil conditions, vigour, drought tolerance and nutrient uptake. Rootstock choice is a major decision when establishing or replanting a vineyard.
Most commercial European wine varieties are Vitis vinifera, which is susceptible to root-feeding phylloxera. Many North American grape species and hybrids have resistance or tolerance to the pest. Grafting a vinifera scion onto a suitable rootstock allows growers to produce the desired grape variety while protecting the root system.
Different rootstocks are suited to different soils and climates. Some tolerate dry or calcareous soils better, while others influence vigour or perform well in heavier or wetter conditions. Rootstock can also affect nutrient uptake and the vine’s response to water stress. The best choice depends on site analysis, variety, spacing and vineyard objectives.
Rootstock provides the roots and lower trunk. Scion is the fruiting variety grafted above the union, such as Cabernet Sauvignon, Chardonnay or Pinot Noir. The rootstock does not determine the grape variety named on the wine label, although it can influence vine performance and fruit composition.
Example: a Pinot Noir scion may be grafted onto a phylloxera-resistant rootstock selected for a cool-climate vineyard’s soil and water conditions.
Chef’s note: rootstock is a viticultural choice, not a wine style or quality designation. It contributes to vineyard performance over the life of the planting.
This term is one of hundreds covered in depth across OCS courses, learning paths, and 1-on-1 coaching with Chef Eric.
