Characteristics of Persian Walnut Tree (Juglans regia) in the Wild

Juglans regia
Persian Walnut (Juglans regia) is the most nutritious nut-producing tree species in the world, originating from the Balkans eastward to the Himalayas and southwest China. The tree is widely cultivated throughout Europe and elsewhere for its fruit. China is a major commercial producer of walnuts.

Juglans regia is commonly referred to as “Walnut”, but more specifically in some countries such as in South Africa it is called Persian Walnut, in North America, United Kingdom, New Zealand, Australia, it is called English Walnut. In Chinese it is called Hu Tao (胡桃), which means literally “Hu peach”, in Mexico it is called Nogal de Castilla, and in Old English it is Wealhhnutu.

One of the regions of origin of Juglans regia is Iran. However, as with other ancient trees, it is not easy to reconstruct the original distribution and determine the boundaries of the natural range of the past. There are many reports of the earliest pollen and bean Juglans regia fossils, and the conclusions drawn by various authors are somewhat contradictory. Taken together, these findings suggest that Juglans regia may have survived the last glaciation in some of the refugia, as the compilation of data suggests most likely southern Europe, China, and the Himalayas.

The largest Juglans regia forest is in Kyrgyzstan, where the trees grow at an altitude of 1,000-2,000 m asl, mainly in Arslanbob in Jalal-Abad Province.

Persian Walnuts contain 4% water, 65% fat, 15% protein, and 14% carbohydrates. In a reference amount of 100 grams providing 654 calories, kernels provide several dietary minerals that are rich in content (20% or more of the Daily Value, DV), including manganese (162% DV), phosphorus (49% DV), magnesium (45% DV). DV), zinc (33% DV), and iron (22% DV) include vitamins B, B6 (42% DV), thiamine (30% DV), and folate (25% DV), and dietary fiber.

One study of various cultivars of Juglans regia in Turkey showed the fatty acid composition including about 6% palmitic acid, 3% stearic acid, 30% oleic acid, 50% linoleic acid, and 9% linolenic acid.

Currently, there are several cultivars of walnuts that are cultivated for fruit harvest, including:

  • Purpurea
  • Broadview
  • Cascade
  • Allegheny
  • Bedco 1
  • Coble #2
  • Hansen
  • Kaiser
  • KY Giant
  • Lake
  • McKinster
  • Somers
  • Utah Giant
  • Colby
  • Greenhaven
  • cool down
  • Shiawasee
  • Perry
  • S-1
  • Looking Glass
  • China-B
  • Champion
  • Northern Prize
  • Placentia

In 2019, the world’s walnut production was 4.5 million tons, led by China with 56% of the total. The second producer is the United States and the third is Iran.


On Skopelos, a Greek island in the Aegean Sea, local legend suggests that anyone who planted a walnut tree would die as soon as the tree “saw” the sea.

In Flanders, a saying goes “By the time the tree is big, the planter will surely die.” This proverb refers to a relatively slow growth rate and late fruition.

Benevento in southern Italy is the home of the ancient tradition of Stregoneria. The witches of the famous Benevento come from all over Italy to gather for the Sabbath, they are under the sacred walnut tree of Benevento.

In 1526, Judge Paolo Grillandi wrote of a witch in Benevento worshiping a goddess at the site of an old walnut tree.


Characteristics of Persian Walnut Leaf

Juglans regia Leaf

The leaves are alternately arranged, 25-40 cm long, pinnate with 5-9 leaflets, alternately paired with one terminal leaflet. The largest leaflets are at the apex, 10-18 cm long and 6-8 cm wide, the base pair of leaflets are much smaller, 5-8 cm long, with the leaflet edges intact.


Characteristics of Walnut Persian Flower

Juglans regia Flower

Male flowers are in drooping catkins 5–10 cm long, and terminal female flowers, in clusters of two to five, ripen in autumn to fruit with semi-fleshy green skin and corrugated brown nuts.


Characteristics of Persian Walnut Fruit

Juglans regia Fruit

The whole fruit, including the skin, falls in autumn, has large seeds, with a relatively thin shell, and is edible, with a rich taste.


Characteristics of Persian Walnut Tree

Juglans regia Tree

Persian walnut grows as a large deciduous tree, reaching a height of 30-35 meters, and a trunk diameter of up to 2 meters. Generally, this tree has a short trunk and broad crown, although it can also be taller and a narrower crown in dense forests.

Persian walnut trees need plenty of full suns to grow well. Grows best in rich, deep soil with full sun and long summers. It is known, Juglans hindsii and Juglans hindsii × Juglans regia are often used as grafting seeds for Juglans regia.

FYI: Other plants often don’t grow under walnut trees because the fallen leaves contain Juglone (a chemical that acts as a natural herbicide).
Characteristics of Persian Walnut


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