Plant · P-536

Arizona Walnut

Juglans major

Arizona Walnut is a fast-growing, drought-hardy tree of dry southwestern stream banks and canyons, producing small, hard-shelled nuts that reward hand cracking with a good kernel. Its thick husk and extremely tough shell make it slow going compared with other walnuts, but it earns its keep as rootstock - Persian and Carpathian walnut grafted onto it thrives on alkaline soils where other walnut rootstocks fail. Its wide, round crown casts useful shade, though the roots and fallen leaves carry juglone, which suppresses sensitive neighbours such as apples.