The Persian walnut (Juglans regia) is a deciduous tree widely cultivated across Europe, but originally found in the mountain region of Central Asia. It is native to the region covering from the Balkans eastward to the Himalayas and southwest China. It is most common in Kyrgyzstan, it is found in nearly pure walnut forests at 1,000–2,000 m altitude.
Other names include common walnut in Britain; Persian walnut in South Africa and Australia; and English walnut in North America and Great Britain, New Zealand, and Australia.
The Persian walnut tree is tall with an average height of 25-35m and a wide trunk. The fruit is green in color, with a semi-fleshy covering and a brown uneven nut. The seed is large, slightly hard and fleshy. It is also a beautiful ornamental plant found in parks all around the world.
Persian Walnut: nut and edible seed. Photo: Henryk Kotowski
Where it grows
The best condition of growth for the trees is rich, deep soil with a weather of full long summer plentiful sunlight. Walnut roots and leaves produce juglone, a chemical that constrains the growth of certain plants. It has to be made sure that the surrounding species are resistant to juglone.
It takes a long time until the fruit can be harvested. Normally plant grown from seed is used for the fine lumber. Grafting from other improved varieties is the best way of growing fruiting plant.
It is hardy to zone (UK) 5 and zone (USDA) 7-9 and can handle frost pretty well. The flowers are monoecious (single sex flowers are found on the same tree) and are wind pollinated. The Persian walnut plant is self-fertile.
Persian walnut: unripe/green fruit. Photo: George Chernilevsky
Why We like it
- The walnut seeds can be eaten raw, cooked and especially roasted for the enhancement of flavor.
- The nuts contain antioxidants which protect the arteries and slow cognitive decline.
- The seed can be used as an excellent wood polish.
- A drying oil is produced from the seeds, which is used in manufacturing soaps and oil paints.
- The Persian walnut produces valuable and high-quality lumber. It is very hard and very pretty and used for flooring, furniture, and things like gunstocks, paddles, and tools.
- A yellow dye is obtained from the green husks, green nuts and leaves.
- A brown dye is produced from the mature husk and leaves.
- The nut shells are used as anti-skid agents for tyres, blasting grit, and in the preparation of activated carbon.
- Dried bark and fruit rind are used as a tooth cleaner.
- The rind of unripe fruit is a good source of tannin.
- Walnuts can be tapped like a maple tree to make syrup.
- The dried fruit rinds can be used to paint doors and frames. The tannin content works as an insect repellent.
Medicinal use:
“The walnut tree has a long history of medicinal use, being used in folk medicine to treat a wide range of complaints[269]. The leaves are alterative, anthelmintic, anti-inflammatory, astringent and depurative[9, 218]. They are used internally the treatment of constipation, chronic coughs, asthma, diarrhoea, dyspepsia etc[9]. The leaves are also used to treat skin ailments and purify the blood[9, 218]. They are considered to be specific in the treatment of strumous sores[240]. Male inflorescences are made into a broth and used in the treatment of coughs and vertigo[218]. The rind is anodyne and astringent[147]. It is used in the treatment of diarrhoea and anaemia[238]. The seeds are antilithic, diuretic and stimulant[218]. They are used internally in the treatment of low back pain, frequent urination, weakness of both legs, chronic cough, asthma, constipation due to dryness or anaemia and stones in the urinary tract[176]. Externally, they are made into a paste and applied as a poultice to areas of dermatitis and eczema[176]. The oil from the seed is anthelmintic[218]. It is also used in the treatment of menstrual problems and dry skin conditions[238]. The cotyledons are used in the treatment of cancer[218]. Walnut has a long history of folk use in the treatment of cancer, some extracts from the plant have shown anticancer activity[218]. The bark and root bark are anthelmintic, astringent and detergent[218, 240]. The plant is used in Bach flower remedies – the keywords for prescribing it are ‘Oversensitive to ideas and influences’ and ‘The link-breaker'[209].” – Plant for the Future
