Black walnut or Eastern black American walnut (lat. Juglans nigra) is a tree species from the Walnut genus of the Walnut family (Juglandaceae). These walnut trees can live more than 500 years, and specialists believe that such an age is not the limit.  It is also one of the most sought-after deciduous species in North America. The natural range of the species is North America and Canada. 1629. black walnut was introduced in Europe and is grown from Italy to Finland.

   Black walnut grows 30-40 meters high, with a dark, almost black skin, covered with deep cracks. The diameter of the trunk can exceed 1.5 m. The leaves are 25-50 cm long, with 11-23 oblong-oval, light green leaflets.

   Black walnut is more frost-resistant than walnut and mature trees can tolerate frost down to -40 ° C, but young trees (up to 3 years old) need protection from frost and winter winds. Black walnut begins to produce fruit 6. up to 9. year of life—fruit ripening-from late September to mid-October. 

   The black walnut belongs to the wind-pollinated monoecious trees. In Latvian conditions, flowering occurs in the second half of May and continues until the beginning of June. The flowering of female and male inflorescences on the tree does not coincide – therefore, several trees are needed for better pollination.

   The soil should be slightly alkaline or neutral. A tree growing on slightly acidic or acidic soil lags in development and is not able to properly prepare for the upcoming winter. Black walnut is distinguished by its moisture-loving nature. Quite often in Indiana, the root system of the plant is flooded. Often it is under water for 4 weeks, but this does not harm the tree. For planting this culture, it is not recommended to choose places located near fruit trees. The leaves of black walnuts secrete a substance – juglone, which has a detrimental effect on plants located near it. However, some trees grow well next to the Canadian Walnut, such as maple, Linden, and hornbeam. But if, nevertheless, you want to grow black walnut along with other crops, you will need to collect fallen leaves from the ground in the fall – this will significantly reduce the effect of juglone on other plants.

   The fruits of the black walnut are green, spherical, or pear–shaped, 3.5-6 cm in diameter. Black walnuts are commercially shelled in the US. About 65% of the annual wild harvest comes from Missouri. They are widely used in ice cream, bakery products, and confectionery. During the fall holiday season, consumers bake black nuts into traditional treats such as cakes, cookies, and pies. Nuts, due to their flavor, are used in other dishes such as salads, fish, pork, chicken, vegetable and pasta dishes. Fruits (nuts) are cultivated for their characteristic and attractive taste. The core of black nuts is very tasty, with a special aroma, but this is not the main characteristic of this tree.

   The components of this plant are also very popular in medicine, in particular in dermatology, neurology, and gastroenterology. Most researchers are attracted by the anti-cancer and antioxidant properties of walnuts, their effect on the heart and blood vessels, and the proven beneficial effect of black walnuts in the treatment of many diseases of the cardiovascular system and the complex therapy of neoplasms. Black walnut is a valuable medicinal plant containing naphthoquinones (juglone, hydroquinone, and their glycosides). These natural compounds are present in different parts of the plant – pericarp, bark, and leaves, and have a wide range of biological effects. ​

   The main component of black walnut is juglon. It is unique and occurs only in representatives of the walnut family. The beneficial effect of the drug, which includes an extract of walnut pericarp, is largely due to the biological activity of juglone.

   Black walnut wood is dark brown, has a beautiful texture, and is one of the most valuable woods in the world. The wood of an adult tree costs several thousand dollars per cubic meter. The wood is heavy, dense, and very durable, but easy to process. Black walnut is one of the most durable hardwoods in the USA – after proper drying, it keeps its shape stably. Black walnut wood is used by furniture manufacturers all over the world, it produces high-quality and expensive furniture, premium plywood, and moldings, and is used to decorate interiors and make musical instruments.