If you can look forward to regular visits from squirrels in your own garden, you may be lucky enough to have the animals start growing new walnut trees for you. It’s not uncommon for the little runabouts to bury local walnuts in the ground, which then germinate. This shows that it is ultimately not that difficult to grow a walnut tree from a walnut. However, the project will take some time. This guide describes how to do this.
Table of Contents
Basic remarks
First of all, it should be noted that a walnut tree requires a lot of space in the garden. The plant is generally 15 to 25 meters high and the crown can reach a diameter of up to 15 meters. Even if it takes decades for the tree to grow fully, you should include these facts in your considerations right from the start.
In addition, the walnut is one of the deep-rooters (the opposite is shallow-rooters) and thus forms a so-called taproot. It is a long, strong root that penetrates vertically deep into the ground. It must therefore also have enough space to develop optimally and to promote the growth of the tree.
Speaking of promoting growth: Like other nut trees, the walnut also needs a lot of light. It must be free by the age of ten at the latest, otherwise it will die again. The walnut only tolerates partial shade in the first few years. It does not make particularly high demands on the soil. It just shouldn’t be extremely dry and poor, then everything is fine.
Furthermore, growing a walnut tree requires a patient hobby gardener. Although it becomes apparent relatively quickly whether the walnuts used are capable of germinating, it takes a lot of time before a real tree develops from them. If you don’t want to wait years for significant flare-ups, it’s better to buy a refined walnut from a tree nursery or online retailer.
Not every walnut is suitable for breeding. For example, it usually makes no sense to buy a pack of walnuts in the supermarket and use them as a base. Normally, these nuts are no longer germinable. But: You can read from some hobby gardeners that it can actually work with walnuts from the store.
In principle, however, breeding with fresh walnuts from a nearby walnut tree is preferable. Experts recommend taking “seed nuts” from a tree in the same area where you want the new sapling to thrive. They argue that the descendants are best able to cope with the circumstances or conditions in the room.In summary, four key points for the cultivation of a walnut at a glance:
- enough space in the garden (down, up and in width)
- free, bright location with soil that is not too dry/poor
- requires a lot of patience on the part of the hobby gardener
- Walnuts from a nearby tree as a first choice
Important: One must not expect that after the germination and growth of the new walnut tree, the result will be the same as that which one might be familiar with from the original tree. The offspring often differ visually and also with regard to the nuts – especially if there is no refinement. And this is only recommended for experienced hobby gardeners.
Cultivation: bucket or right in the garden?
In principle, both variants are possible. It is only important that the young walnut gets the place where it should stay after a year and a half at the latest.
If you want to accept the challenge and refine your walnut yourself, you are also free to decide whether you prefer to grow them in tubs or in gardens. For practical reasons, however, it is advisable to choose cultivation in a bucket if in doubt.
Instructions for growing in the bucket
Preliminary remark: It is best to start growing in autumn. Use fresh nuts (not old ones).
1st step: Prepare a large flowerpot with a sand-peat mixture.
Step 2: Carefully remove the green peel from the selected fruit.
Step 3: Put several nuts in the pot and dig in about five to ten centimeters deep.
Step 4: Place the flowerpot with the nuts in a bright and sheltered (permanently frost-free!) location.
Step 5: Leave the pot until next spring. Keep the soil constantly moist (but not too wet).
Step 6: Wait until the shoots are about 15 centimeters long.
Step 7: Divide the individual plants – so put each one in its own (large) pot.
Step 8: Place the pots in the garden over the summer months. A sunny location is important, but the soil must never dry out.
Step 9: Place the young trees in a frost-free place for the winter. At this point they are not yet hardy.
Step 10: Plant the young trees firmly in the garden the following spring.
Instructions for growing in the garden
Step 1: Collect or buy walnuts and carefully remove their shells if necessary.
Step 2: Choose an open and bright location in the garden.
Step 3: Plant the nuts five to ten centimeters deep in the ground.
Step 4: Add compost to encourage growth.
Step 5: Keep the site constantly moist (not wet).After cultivation in autumn, white root shoots and green leaf shoots appear in spring. In the first year, the tree grows a maximum of 30 centimeters. Then carry out the usual care measures for the walnut (there is a summary of this at the very end of this article) and wait patiently for the slow changes.
Refine walnut yourself – this is how it works
The so-called WalWal-Stubenveredlung, developed by the Swiss Hans-Sepp Walker, is a very simple way of refining the walnut yourself. Nevertheless, you should have some experience in gardening in order to understand the task in detail and to be able to master it successfully.
Here is a brief overview of the advantages of a refinement:
- Tree becomes more robust
- grows faster
- bears fruit earlier, more fruit, and larger fruit
Of course, all of this speaks in favor of refining your own walnut. This is how you proceed step by step:
Preliminary remark: It is best to start in December (in the case of seedlings growing outdoors only if the ground is not frozen).
Step 1: Use one or two year old seedlings as a base. These should be between one and three centimeters thick at the finishing point.
Step 2: Place the seedlings in pots of potting soil (two to ten seedlings per pot, depending on the size of the seedlings and pots).
Step 3: Place pots with seedlings in a permanently warm and bright place at around 20 degrees.
Step 4: Put a plastic bag over each pot.
Step 5: Leave it like this for about three weeks – until the buds start to sprout (and the tree sap starts to rise). Then the seedlings are ready for grafting.
Step 6: Cut several scions from a beautiful walnut tree immediately before grafting.
7th step: Make the actual refinement cut with copulation. In detail:
- 7a) Prepare a base, scion, sharp garden knife, raffia, scissors, liquid tree wax and a brush.
- 7b) Make an oblique cut of about six centimeters in the underlay – with the sharpest possible garden knife.
- 7c) Now make the same sloping, approximately six centimeter long cut with the scion.
Step 8: Lay the two interfaces on top of each other (copulate) and connect them with bast. Wrap tightly, tie a knot at the end and cut off the excess with scissors.
Step 9: Coat the grafting point and the end of the scion with liquid tree wax (don’t be too sparing).
Step 10: Repeat the procedure with several seedlings and shoots.
Step 11: Put the grafted seedlings back into pots with potting soil and keep them indoors at 20 degrees Celsius.
This is how it goes on:
- After about ten days, buds will sprout from the rootstock.
- After about three weeks, the callus forms and the buds of the scion begin to sprout. It is then advisable to remove the plastic bags completely.
- After just eight weeks, the shoots are between 30 and 50 centimeters high. This shows how much faster grafted walnut trees grow (ungrafted trees usually take at least a year to reach 30 centimeters).
- In the spring, when there are no more frosts, the young trees are planted in the garden at the designated locations.
- With a bit of luck you can harvest the first good nuts five years later (otherwise, i.e. without refining, it takes five to ten years longer).
Care of the young walnut trees
Finally, some tips for caring for the growing walnut trees after propagation and (possibly) grafting:
a) Water the trees regularly for at least two years after planting. But it is important to avoid waterlogging. So you only water when the soil is almost dry.
b) Always remove moss and weeds around the trees and mulch larger and woody plants.
c) Fix each tree with a wooden pole. Simply loop a rope around the walnut tree and the post. This provides the necessary stability.
d) Do not fertilize young plants yet. Do not start adding fertilizer until they are one and a half meters tall.
e) Keep a constant eye on the growing trees and watch closely for pests and/or diseases. If necessary, take countermeasures immediately.
f) Shorten the lower branches (those that are not part of the basic structure) regularly. This supports straight growth.
g) In theory, young trees can still be transplanted, even if it is not advisable to do so. Once the plants are over three years old, it is imperative that they remain in place.
