Juglans Regia and Juglans Nigra
Walnuts are not only delicious but also incredibly nutritious, making them a wonderful addition to a healthy diet and a great tree to have in your forest garden. These brain-shaped nuts are packed with essential nutrients and offer a wide range of health benefits.
Healthy and Nutritious
Walnuts are an excellent source of alpha-linolenic acid (ALA), an essential omega-3 fatty acid thought to help reduce the risk of heart disease. They are also rich in antioxidants, which are believed to fight oxidative stress and inflammation in the body, potentially reducing the risk of chronic diseases as well as helping to support brain health and improve cognitive function.
Despite being calorie-dense, walnuts can aid in weight management due to their high protein and fibre content, which can promote feelings of fullness. Recent studies have shown that the high levels of protein, fibre, vitamins and minerals found in walnuts may help improve blood sugar levels, making them beneficial for individuals with or at risk of developing type 2 diabetes.
Walnut Trees
Most of the named cultivars of walnut tree in the UK are Juglans Regia, known as English Carpathian Walnuts, although originally they came from Persia. They are hardy with thin shelled nuts which are easy to crack and have a full flavour with a hint of sweetness and butterscotch, great for eating fresh, cooking and baking. Although they are self-pollinating they will produce greater yields when planted with another variety, producing harvestable nuts September-October.
We have a number of Juglans Regia at The Fruitful Forest Garden, some of which are named cultivars. The most productive named cultivars are thought to be Buccaneer and Broadview, however at the Fruitful Forest it is Red Danube that has been most productive so far.
Juglans Nigra, or Black Walnut, is native to Eastern North America where it is prized for high quality wood. The black walnut is much faster growing than the English walnut which is another reason that it is often planted for wood. The nuts have much thicker skins and are notoriously difficult to crack and have an earthier taste compared to the English walnut. They are also more shade tolerant than English walnut.
Companion planting with walnuts
Both Juglans Regia and Juglans Nigra are members of the Juglans genus, who all produce a non-toxic, colourless, chemical called hydrojuglone, with Julgans nigra secreting more than Juglans regia. Hydrojuglone is found in leaves, stems, fruit hulls, inner bark and roots. When exposed to air or soil compounds, hydrojuglone is oxidized into the allelochemical juglone, which is toxic to some other plants. Gardeners are often advised never to plant walnuts within 50m of apple trees as they are highly sensitive to juglone.
If you have a healthy soil food web then much of the juglone will be metabolically decomposed by the microbes and animals in the soil, rendering it harmless. This is often the case in forests and forest gardens and would explain why I remember seeing many walnuts trees in Graham Bells forest garden surrounded and underplanted with a wide variety of very healthy looking and highly productive fruit trees, including apples. However, if you have poor soil, eg in an urban landscape, then it is best to look for compatible plants to combine with your walnuts.
Trees and shrubs that are tolerant to walnuts include ash, birch, Elderberry, crabapple, hawthorn, honeysuckle, hydrangea, lilac, privet, sumac and viburnums.
Herbs and ground covers that are compatible with walnuts include yarrow, day lily, calendula, primrose, daffodils, ferns, hostas, siberian iris, hollyhocks, raspberries and mullein
One last thing to say about walnuts is that you do need to have some patience. They can take 10-20 years to fruit – so you can imagine our surprise when ours fruited after only 5 years!
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