Juglans "J. regia", "Juglans" x Paradox, are widely used as rootstocks for "J. regia" cultivars because of their resistance to Phytophthora and to a very limited degree, the oak root fungus. However, trees grafted on these rootstocks often succumb to black line. In some countries, immature nuts in their husks are preserved in vinegar. In the UK, these are called pickled walnuts and this is one of the major uses for fresh nuts from the small scale plantings. In Armenian cuisine, unripe walnuts, including husks, are preserved in sugar syrup and eaten whole. In Italy, liqueurs called Nocino and Nocello are
Fruit tree propagation cultivars of a single species, known as a family tree, or, within certain limits, cultivars of different fruit species on one tree, often known as a fruit salad tree. Family trees typically combine several cultivars (two or three being most common) of apple, pear or a given species of stonefruit on a single rootstock, while fruit salad trees typically carry two or more different species from within a given genus, such as plum, apricot, and peach or mandarin orange, lemon, and lime. Certain combinations, including sour cherry ("prunus cerasus")/sweet cherry ("prunus avium"), although from the same genus, are known to