Walnuts are fast growing trees that develop broad canopies reaching 18m width and 30m in height. It is a light-demanding species, requiring full sun to grow well.
The buds awaken from winter dormancy in mid April - late May (depending on cultivar) and leaf fall occurs in early November. The large compound leaves give off a lemon / lime scent particularly when crushed. The flowers open before or around the same time as the leaves and you can find both male and female flowers on the plant (monoecious).
The male flowers are slender catkins and the female flowers are smaller, often found on the tips of the branches. Pollination is carried out by the wind.
Common name: Persian walnut, common walnut, English walnut, Carpathian walnut and Madeira nut.
Bloom time: Early spring, Late spring, Mid spring. Form: Rounded.
Height: Juglans regia is a large, deciduous tree attaining heights of 25–35 m, and a trunk up to 2 m diameter.
Difficulty level: Moderate
Planting & Care
Sunlight: Full sun. It cannot grow in the shade.
Soil: Moist but well-drained; Chalk, Clay, Sand, Loam soil
Water: Should not be necessary unless rainfall is below 600mm per year and is uneven in distribution throughout the year. In my climate in southeast Europe, Bulgaria, I give my young trees 20L once every two weeks during the summer months. Never use a sprinkler or hose to water and avoid splashing water onto the leaves as this will promote the development of blight.
Fertilizer: It s advisable to not add compost to the roots of walnuts when planting out and to add just a little top dressing compost to your newly planted trees. In the 2nd year, adding around 10L of compost to the base of the tree in the spring will meet the plants growing nitrogen demands. Too much nitrogen makes the trees more susceptible to walnut blight.
- Walnuts have both male and female flower parts on the same tree.
- The pollen is shed from the male flowers and should settle on the females flowers.
- The pollen is physically very small and light and can travel quite some distance.
- Studies have shown in certain orchards that wind blown pollen came from trees over a mile away.
- If the pollen from the male flower settles on the female flower when they are receptive, fertilisation is likely to occur and the female flower will develop into nuts.
- The time of pollen shedding from the male flowers does not always overlap well with the time of female flower receptivity to pollen.
- This condition is referred to as dichogamy.
- To overcome this problem growers can select another walnut cultivar (a pollinator), the male flowers of which open at the same time as the female flowers from the main cultivar.
- The pollinator should be situated upwind from the main crop.
- If you have other walnuts upwind from your site you should not have problems with this.
- Nearly all commercial orchards are co-planted with a pollinator variety to ensure the main crop gets enough pollen to set nuts.
- The recommendations for optimal pollination in an orchard environment is to plant one row of pollinators for every eight main crop rows and to plant the row of pollinators upwind.
- Weeding - It s important to keep the trees free from weeds whilst they establish, as young trees are intolerant of competition especially from grass.
- Mulching the trees annually with card and straw will work well but take care to keep the collar free from mulch to prevent it from rotting.
- Sunburn: can occur in excessive summer heat (38°C) and the kernels can shrivel and darken.
- This is more so of a problem if the tree is under moisture stress.
- Cold injury: Young trees are very susceptible to frost damage.
- Flowers can be destroyed in early frosts so it s important to select late flowering cultivars if your planting site experiences early frosts.
- Insect/Pest: Codling moth (Cydia pomonella), navel orangeworm (Amyelois transitella), walnut husk fly (Rhagoletis completa), aphids, scales and mites; nematodes (Pratylenchus vulnus).
- Disease: Blight (Xanthomonas campestris); blackline (cherry leafroll virus); root and crown rots (Phytophthora spp.
- , Armillaria mellea); deep bark canker (Erwinia rubrifaciens); crown gall (Agrobacterium tumefaciens).
- The walnut tree has a long history of medicinal use, being used in folk medicine to treat a wide range of complaints
- 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 a sugar.
The finely ground shells are used in the stuffing of agnolotti pasta.
- They have also been used as adulterant 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 a tea.
Wednesday, 18 March 2020
Sunday, 01 March 2020
Wednesday, 19 February 2020
Please log in to write a review. Log in