In Europe, in general, is used the franco rootstock: Juglans Regia. It has good affinity with cultivated varieties. Depending on the source, has a root system consisting of more or less fine roots, which facilitates a better reaction to transplantation.

It also was used in black walnut: Juglans nigra. Their advantage is a higher tolerance to root diseases, mainly Phytofthora. However, it is sensitive to Black-line, a disease caused by cherry leafroll virus, which is not tolerated by J.Nigra but for J.Regia, bringing the infection to the point of grafting and it dries the top of the tree. This practice has led to its total elimination as rootstock.

In U.S. the most used rootstock is Paradox, a hybrid of Juglans hindsii (California black walnut) and J. Regia. However there have been great failures because of Black-line, which has led them to seek new rootstocks.

Now in Europe, are used two hybrid rootstocks: mj 209xRa and Ng23xRa developed for plantations for wood, with great vigor and well adapted to alkaline soils. The first results in use as rootstocks for fruit varieties, are encouraging for its vigor and uniformity. There is no experience of many years, to talk about its sensitivity to Black-line. It comes from crossbreeding between J. Regia x J.Nigra and the result with another crossbreeding with J. Regia. Currently it's multiply by seeds from trees isolated and controlled, waiting to get them multiplied in-vitro plantations.

In U.S. it's used the Vlach, a clonal paradox of great vigor, multiplied in-vitro, and two new rootstocks: RX1 and VX211, clonal multiplied in-vitro, selected for resistance to nematodes, root diseases, etc. RX1 is Phtopthora moderately resistant, moderately vigorous and is being tested the nematode resistance. VX211, another paradox is considered nematode tolerant. So far they are not available in European nurseries.

A study rootstock is the Pterocarya stenoptera, which has the highest known resistance to Phytophthora, but with lack of affinity in some varieties. Apparently also has better tolerance to nematodes than other rootstocks.

Other rootstocks are being studied in France and the United States, which will be available in the coming years.