The heartnut is a Japanese walnut variety whose nuts are heart-shaped and crack out easily in two halves. The tree is resistant to many diseases that afflict black walnuts and butternuts, but is susceptible to walnut bunch disease. The flavor of the heartnut is similar to grocery store walnuts but without any bitterness. The tree can grow very quickly once established. The branches on heartnuts reach out in a wide, spreading form, and the large compound leaves give the tree a majestic look.