Your own walnut tree is a promise to the future. It grows slowly into a mighty, shade-giving tree and bears for decades, often for the next generation too. Yet it is exactly this size that undoes many who unknowingly plant the sapling next to the terrace.
Two things you should know before planting: how large the tree becomes and why you do not buy a seedling. Take both to heart and you have decades of pleasure and full nut harvests. This article shows you what matters.
Consider the size first
The walnut is not a tree for the small terraced-house garden. Over the years it grows huge, with a widely spreading crown that casts a lot of shade. Planted too close to buildings, paths or beds, it becomes a permanent problem. Reckon on a final distance of at least ten metres to anything sensitive.
On top of that comes a special feature: leaves and roots give off juglone, a natural inhibitor. Little therefore grows under an established walnut, and the falling leaves do not belong on every bed. That is not a disease but the nature of the tree.
Grafted, not a seedling
The second important point is the tree's origin. A cheap seedling from a pip takes a very long time to bear, often 10 to 15 years, and what quality the nuts have is a gamble.
A grafted tree of a named early-cropping variety, by contrast, bears within a few years and reliably brings large, well-kernelled nuts. Varieties such as 'Geisenheim 26' or 'Weinsberg 1' are bred for our climate. The higher price pays off in years of earlier harvest. The principle of grafting is explained in Grafting fruit trees.
Spot and planting
The walnut wants a full-sun, deep soil and a spot as free of late frost as possible. Its leaves emerge early and are sensitive to late frosts, which strike especially hard in a hollow. It is planted like any fruit tree, bare-root in the dormant season.
Plan plenty of space and buy a grafted tree, not a seedling. Then the walnut bears early and becomes a tree for generations.
The core rule on the walnut
Frequently asked questions
How big does a walnut tree get?
Very big, often 15 metres and more, with a broad, widely spreading crown. Plan at least ten metres' distance to buildings and beds. For the small garden the walnut is usually too large.
Why does nothing grow under my walnut?
Because roots and leaves give off juglone, a substance that inhibits many other plants. That is normal. The area under the crown naturally stays rather bare, and the leaves do not belong on sensitive beds.
Should I buy a grafted tree or a seedling?
A grafted tree of a named early-cropping variety. It bears within a few years and reliably brings good nuts. A seedling takes 10 to 15 years, and the nut quality is uncertain.
When does a walnut first bear?
A grafted tree often as early as its third to fifth year. A seedling, by contrast, only after 10 to 15 years. That is why the slightly dearer grafted tree almost always pays off.
Do I have to prune a walnut?
As little as possible. Walnuts bleed heavily when pruned in the sap season. Necessary corrections are made in late summer after harvest. Best build a good framework early, then the tree stays almost prune-free later.
