Juglans regia: How to Grow English Walnut in Australia

Juglans regia (Walnut) is a Tree which grows to a height of 20m and a width of 20m . It has a moderate growth rate. It has a hardness rating of 5 and is quite resilient to frost.

Walnut will flower in December. the seeds ripen from April.

The flowers from this plant are monoecious (both sexes are found on the plant but each flower is either male or female) and they are pollinated by wind.

Juglans regia Growing Guide

Soil Information

Walnut will grow in light (sandy),medium (loamy),hard (clay) soil. It is / is important for the soil to be well drained.

The soil prefers the following PH / acid levels :

• pH of less than 6, Acidic soils
• pH between 6 and 8, Neutral soils
• pH greater than 8, Basic soils

Walnut prefers moist soils

Ideal Planting Locations

Walnut should not be planted in shady areas.

Forests in the Himalayas, preferring a northerly aspect in the west but a southerly or westerly aspect in the east of the range.

Planting places suited to this plant described below.

• Grows within a woodland garden
• Is suited as a canopy tree

Juglans regia Cultivation Details

Requires a deep well-drained loam and a sunny position sheltered from strong winds. Prefers a slightly alkaline heavy loam but succeeds in most soils. The walnut tree is reported to tolerate an annual precipitation of 31 to 147 cm, an annual temperature in the range of 7.0 to 21.1°C and a pH in the range of 4.5 to 8.2.

The dormant plant is very cold tolerant, tolerating temperatures down to about -27°C without serious damage, but the young spring growth is rather tender and can be damaged by late frosts. Some late-leafing cultivars have been developed, these often avoid damage from spring frosts and can produce a better quality timber tree.

The walnut tree is frequently cultivated for its edible seed in temperate zones of the world, there are many named varieties. Newer cultivars begin producing nuts in 5-6 years; by 7-8 years, they produce about 2.5 tons of nuts per hectare.

Orchards on relatively poor, unirrigated mountain soil report 1.5-2.25 tonnes per hectare, orchards in well cultivated valleys, 6.5-7.5 tonnes per hectare. According to the Wealth of India, a fully grown individual can yield about 185 kg, but 37 kg is more likely.

Trees grow well in most areas of Britain but they often fail to fully ripen their fruits or their wood in our cooler and damper climate, they prefer a more continental climate. There are some very fine trees in Cornwall. Walnuts can produce large healthy trees in many parts of Britain, but seedling trees often do not fruit reliably.

Some European varieties have been developed that succeed in colder areas. Seedling trees are said to take from 6 to 15 years to come into fruit from seed, but these cultivars usually start cropping within 5 years.

Plants produce a deep taproot and they are intolerant of root disturbance. Seedlings should be planted out into their permanent positions as soon as possible and given some protection for their first winter or two since they are somewhat tender when young.

Flower initiation depends upon suitable conditions in the previous summer. The flowers and young growths can be destroyed by even short periods down to -2°C, but fortunately plants are usually late coming into leaf.

Some cultivars are self-fertile, though it is generally best to grow at least two different cultivars to assist in cross-pollination. Any pruning should only be carried out in late summer to early autumn or when the plant is fully dormant otherwise wounds will bleed profusely and this will severely weaken the tree.

Plants produce chemicals which can inhibit the growth of other plants. These chemicals are dissolved out of the leaves when it rains and are washed down to the ground below, reducing the growth of plants under the tree.

The roots also produce substances that are toxic to many plant species, especially apples (Malus species), members of the Ericaceae, Potentilla spp and the white pines (certain Pinus spp.). Trees have a dense canopy which tends to reduce plant growth below them.

All in all, not the best of companion trees, it is also suggested that the trees do not like growing together in clumps. Trees are said to inhibit the growth of potatoes and tomatoes. Hybridised with J. nigra. This species is notably susceptible to honey fungus. The bruised leaves have a pleasant sweet though resinous smell.

Edible Uses*

* See disclaimer

Edible Rating: 4/5

Seed - eaten raw or used in confections, cakes, ice cream etc. A delicious flavour. The seed can also be ground into a meal and used as a flavouring in sweet and savoury dishes. The unripe fruits are pickled in vinegar.

An edible oil is obtained from the seed, it should not be stored for any length of time since it tends to go rancid quickly. The oil has a pleasant flavour and is used in salads or for cooking. The sap is tapped in spring and used to make sugar.

The finely ground shells are used in the stuffing of 'agnolotti' pasta. They have also been used as adulterants of spices. The dried green husks contain 2.5 - 5% ascorbic acid (vitamin C) - this can be extracted and used as a vitamin supplement. The leaves are used as tea.

• Oil -
• Sap - usually of trees and usually but not always used as a drink.
• Seed - includes nuts, cereals, peas and beans.
• Sweetener - includes sugar substitutes.
• Tea - the various herb teas that can be used in place of tea, plus the genuine article.

Juglans regia Medicinal Uses*

* See disclaimer

Medicinal Rating: 3/5

The walnut tree has a long history of medicinal use, being used in folk medicine to treat a wide range of complaints. The leaves are alterative, anthelmintic, anti-inflammatory, astringent and depurative. They are used internally for the treatment of constipation, chronic coughs, asthma, diarrhoea, dyspepsia etc.

The leaves are also used to treat skin ailments and purify the blood. They are considered to be specific in the treatment of strumous sores. Male inflorescences are made into a broth and used in the treatment of coughs and vertigo.

The rind is anodyne and astringent. It is used in the treatment of diarrhoea and anaemia. The seeds are antilithic, diuretic and stimulant. 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.

Externally, they are made into a paste and applied as a poultice to areas of dermatitis and eczema. The oil from the seed is anthelmintic. It is also used in the treatment of menstrual problems and dry skin conditions.

The cotyledons are used in the treatment of cancer. Walnut has a long history of folk use in the treatment of cancer, some extracts from the plant have shown anticancer activity. The bark and root bark are anthelmintic, astringent and detergent.

The plant is used in Bach flower remedies - the keywords for prescribing it are 'Oversensitive to ideas and influences' and 'The link-breaker'.

• Alterative - Causes a gradual beneficial change in the body, usually through improved nutrition and elimination, without having any marked specific action.
• Anodyne - Relieves pain, it is milder than an analgesic.
• Anti Inflammatory - Reduces inflammation of joints, injuries etc.
• Astringent - Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.
• Bach - Plants used in the Bach flower remedies.
• Blood purifier - Purifies the blood.
• Cancer - Used in the treatment of cancer.
• Depurative - Eliminates toxins and purifies the system, especially the blood.
• Detergent - A cleansing agent, used on wounds etc. It removes dead and diseased matter.
• Diuretic - Acts on the kidneys, promoting the flow of urine.
• Laxative - Stimulates bowel movements in a fairly gentle manner.
• Lithontripic - Removes stones from the kidney, bladder etc.
• Pectoral - Relieves respiratory diseases, a remedy for chest diseases.
• Skin - Plants used in miscellaneous treatments for the skin.
• Stimulant - Excites or quickens activity of the physiological processes. Faster acting than a tonic but differing from a narcotic in that it does not give a false sense of well-being.
• Vermifuge - Expels and kills internal parasites.

English Walnut Propagation

The seed is best sown as soon as it is ripe in individual deep pots in a cold frame. You need to protect it from mice, birds, squirrels etc. The seed usually germinates in late winter or the spring. Plant out the seedlings into their permanent positions in early summer and give some protection from the cold for their first winter or two. 

The seed can also be stored in cool moist conditions (such as the salad compartment of a fridge) over the winter and sown in early spring but it may then require a period of cold stratification before it will germinate. Named varieties are propagated by budding.

Scented parts of the Juglans regia 

Leaves: Crushed

Other Uses of English Walnut

A yellow dye is obtained from the green husks. It is green. The green nuts (is this the same as the green husks?) and the leaves are also used. The rind of unripe fruits is a good source of tannin. A brown dye is obtained from the leaves and mature husks.

It does not require a mordant and turns black if prepared in an iron pot. The dye is often used as a colouring and tonic for dark hair. The leaves and the husks can be dried for later use. A golden-brown dye is obtained from the catkins in early summer.

It does not require a mordant. A drying oil is obtained from the seed. It is used in soap making, paints, etc. It is not very stable and quickly goes rancid. The nuts can be used as a wood polish. Simply crack open the shell and rub the kernel into the wood to release the oils. Wipe off with a clean cloth.

The dried fruit rind is used to paint doors, window frames etc (it probably protects the wood due to its tannin content). The shells may be used as anti-skid agents for tyres, blasting grit, and in the preparation of activated carbon.

The leaves contain juglone, which has been shown to have pesticidal and herbicidal properties. The crushed leaves are insect repellent. Juglone is also secreted from the roots of the tree, it has an inhibitory effect on the growth of many other plants.

Bark of the tree and the fruit rind are dried and used as a tooth cleaner. They can also be used fresh. Wood - heavy, hard, durable, close grained, seasons and polishes well. A very valuable timber tree, it is used for furniture making, veneer etc.

• Dye - Plants that provide dyes.
• Herbicide - Plants or plant extracts that can inhibit the growth of other plants.
• Miscellany - A rag-bag of items that are difficult to categorise.
• Oil - Vegetable oils have many uses, as lubricants, lighting, soap and paint making, waterproofing etc. This does not include the edible oils unless they are also mentioned as having other uses.
• Paint - Plants used directly as a paint. Does not include oil plants and dyes that can be used as ingredients in paints.
• Polish - Plants used to give a shine to metals, wood etc.
• Repellent - Plants that are said to deter but not necessarily kill various mammals, birds, insects etc.
• Tannin - An astringent substance obtained from plants, it is used medicinally, as a dye and mordant, stabiliser in pesticide etc.
• Teeth - Plants used to clean and care for the teeth.
• Wood - A list of the trees and shrubs that are noted for having useful wood.

Cultivars

• 'Broadview' - A medium to large nut with a soft, well-sealed shell of good cracking quality. It ripens slightly earlier than the cultivar 'Franquette', beginning in September, and keeps well. The tree is late coming into leaf and very hardy. It is probably also apomictic, forming nuts without pollination. A very productive, lateral-bearing tree, it is very hardy. The tree is somewhat smaller than seed-grown walnuts.
• 'Buccaneer' - Produces an abundant crop of seeds. A self-fertile cultivar, it produces pollen over a long period and is thus a valuable pollinator for other cultivars. The tree is about the same size as a seedling walnut, it comes into leaf very late and so usually avoids damage by late frosts.
• 'Coenen' - A prolific cropper with large nuts. At least partially self-sterile, the cultivar 'Buccaneer' is a good pollinator. A strong growing tree.
• 'Franquette' - A medium to large nut with a well-sealed thin shell, it has a very good flavour. A large tree, it is partially self-fertile but has relatively low yields and lacks lateral-bud fruitfulness. The cultivar
• 'Buccaneer' is a good pollinator. Very late coming into leaf, it is not susceptible to spring frost damage. It is slow to come into bearing, but is long-lived. This cultivar is not as well suited to the British climate as some of the newer cultivars.
• 'Number 16' - Very similar to 'Rita', but rather more vigorous, it flowers earlier than most other varieties. Cropping prolifically, it is very hardy and self-fertile.
• 'Plovdivski' - The tree forms a broad crown and produces large nuts of excellent flavour. At least partially self-sterile, the cultivars 'Buccaneer', 'Coenen' and 'Rita' are good pollinators.
• 'Proslavski' - Stronger growing than 'Plovdivski', it produces large nuts of excellent flavour. At least partially self-sterile, the cultivar 'Buccaneer' is a good pollinator.
• 'Rita' - A small growing tree, it flowers earlier than most other varieties. Cropping prolifically, it is very hardy and self-fertile.

References

Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement.

• Bean. W.
• Author: Bean. W.
• Publisher: A classic with a wealth of information on the plants, but poor on pictures.
• Date of Publication: 1981

The New RHS Dictionary of Gardening. 1992.

• Huxley. A.
• Author: Huxley. A.
• Publisher: Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
• Date of Publication: 1992