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
Juglans hindsii ("Quercus" spp.) and Fremont cottonwood ("Populus fremontii") trees. "Juglans hindsii" has only one confirmed native stand remaining. It is listed as Seriously Endangered on the California Native Plant Society Rare Plant Inventory. The IUCN classification is a Vulnerable species. It is threatened by hybridization with orchard trees, urbanization, and habitat conversion to agriculture. "Juglans hindsii" is a medium-sized tree of short bulky proportions. It grows up to tall, has a single erect trunk, commonly without branches for , and a crown that can be wider than the tree is tall. Trunks commonly reach in diameter near the base of the