The heartnut is a native of Japan that is well suited to the Great Lakes fruit growing regions (zone 6), a region similar to its native regions in Japan. The nut is named after the shape of the nut.It is considered a seed sport of the Japanese walnut and not a different species. The Japanese walnut is an oval nut, unlike the heart shaped form of the heartnut. The Japanese walnut usually cracks out very poorly, making it unsuitable for commercial production. There are no selected common Japanese walnuts in propagation. They tend to be hardier than the heartnut form of the nut and so efforts should be made to find improved cracking Japanese walnut selections for colder regions. When heartnut seeds are planted, a wide variety of nut shapes and sizes can be produced by the offspring, from good and poor cracking types to oval, very poor cracking, typical Japanese nuts. For this reason, commercial orchards are not advised to plant seedling heartnut trees, but should plant only grafted trees. Though the heartnut tree will grow in colder regions than zone 6, it can be affected by late frosts. Since the tree is terminal bearing, the nut flowers are housed in the tip buds of the trees. These buds are the first to open in the spring and are sensitive to cold spells in April and May. Frost injured flowers will abort and so reduce the crop.
Last edited by Doug Waterman; 05/23/08 12:24 AM.
