It is a large tree with a wide crown.
It is a more vigorous rootstock than that of J. nigra.
It is more resistant to drought than J. nigra.
It requires temperate to cold temperate climates, they resist winter cold well and are susceptible to out-of-season frosts.
It adapts to all types of soils, except that they are compact and poorly drained.
The pattern-graft affinity is very good.
It is sensitive to root asphyxia.
Very resistant to Black-line.
He suffers from iron chlorosis in his with a pH greater than 8.
The roots are prone to rot (Armillariamellea), ink disease (Phytophtoracínnamoni), and crown gall (Agrobacteriumtumefaciens), it does not have resistance to nematodes (Pratylenchusvulnus).
The varieties grafted on J.regia, enter fruiting one year later, at most, than those grafted on J. nigra.

Hybrids between American black walnut and common walnut are called Paradox.
One of the first Paradoxes was the Vlach, a hybrid between, probably, J. hindsii and J. regia. Although Paradox is the best known hybrid, there are other names (Mj209xRa; Ng23xRa; Ng38xRa; among the best known) that are grouped in the taxonomic classification of Juglans x intermedia Carr.
They present enormous vigor and uniformity in the development of the plantations.
Very well adapted to alkaline soils and they resist waterlogging well. Paradoxes, in general, are sensitive to winter cold.
Its roots are resistant to nematode attack and its behavior against ink and rot is not well known, it is resistant to neck disease.
In California, the trees grafted on this rootstock grow and produce more than those grafted on J. hindsii, also giving the walnut more thickness.

It comes from a cross J. nigrax J. regia.
The vigor of the plants is greater than that of their parents, showing superior growth, shape and rusticity.
It has a resistance to ink and is sensitive to rot.
Plants grafted on this pattern are very vigorous

Variety selected by UC Davis – California in 1979, highly appreciated for the great quality and size of its fruit, and with a very light grain color. Moderately vigorous tree, semi-upright and medium-sized. Medium-late sprouting and late harvest. They are mainly used as pollinators Franquette and Fernette.

Californian variety with 80 – 90% side fruiting. Sprouting slightly earlier than Chandler. Small tree of semi-vertical growth that presents a low vigor, and therefore suitable for high density plantations. The harvest is usually before Chandler. Good quality large sealed walnut and a clear grain. Franquette and Cisco pollinators.

Variety selected by UC Davis – California in 1979, presents good vigor and high production. Sprouting generally occurs after the Serr variety, about two weeks, and one week before Chandler. It is harvested a week before Chandler and produces a good quality, filling, large caliber nut.

Early and moderately vigorous variety that presents high production and 100% lateral fruiting. Harvest is similar to Serr, taking place one month earlier than Chandler . Used in very dry climates. Oval walnuts with a fine shell. Pollinators Payne and Serr.

French variety very productive and precocious of fruits with a high caliber. Quick entry into production. Medium bud with numerous lateral buds. Fernette pollinator.

French variety obtained by the INRA that produces fruits of good size and quality. Variety of medium vigor, early, sprouting and late harvesting, and with good productivity. Yield 48%. Fernette pollinator.

French variety crossed between Chandler and Lara. Sprouting is located between Chandler and Fernor, presenting some risk from early frosts. It produces a large, high quality walnut with a slightly higher production than Franquette.

French variety that presents a slow entry into production and reduced production, demanding in cold hours. Flowers only on terminal shoots. Fruit with an excellent taste quality. It requires extra-late polishers. It is currently used as a pollinator.

French variety obtained from the crossing of Franquette and Lara in 1978. Medium vigor and semi-straight habit. Good productive variety, used for pollination of Lara and Chandler . Large fruit and fragile skin.

Excellent French variety of rapid entry into production. Pollinator suitable for the flowering of Franquette and the end of Lara.