Walnut tree bleeds profusely
A real walnut tree (Juglans regia) grows slowly but steadily to an impressive 25 meters high. Nut trees that are grafted onto black walnut (Juglans nigra) and suitable for gardening also reach impressive heights with a crown diameter of 8 to 10 meters. Reason enough to raise a walnut tree at a young age and subject it to occasional pruning as it gets older. If it weren't for the massive flow of sap that comes with every cut, no matter how small.
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In the middle of the growing season, real torrents of sap flow from an open wooden body. The cause is the strong sap pressure, which is at its highest level in spring and only subsides in the course of summer.
Bleeding is not life threatening
Streams of sap on the walnut tree are often a headache for amateur gardeners. There is great concern that the so-called bleeding could cause the splendid tree to die. In fact, it is a natural response to wounds of all kinds, as is known from other tree species, such as spherical maple.
You can't stop the flow of juice. Tree wax (€ 5.99 at Amazon *) and other wound closure agents do not adhere to the soaked surface. Burning out cuts destroys the valuable dividing tissue (cambium) under the bark. Wound healing is impossible without the cambium, so the wound will never close. The remedy of choice against bleeding on the walnut tree is a wisely chosen time of pruning.
Cut in early autumn
If you have prescribed a pruning for your walnut tree, the best time to prune is in early autumn. At the same time as the leaves are shed, the flow of sap is temporarily reduced to a tolerable level. The tree is preparing for hibernation and now no longer wants to grow. A cut date at the beginning of October scores with three important advantages:
- Juice pressure at the lowest level of the year
- Sufficient time window for wound healing until the first frost
- Choice of dates in accordance with the Federal Nature Conservation Act
From October 1st, the Federal Nature Conservation Act allows pruning measures on all types of wood, because the birds' breeding season has ended at this point. Although the new grace period does not start again until March 1st, the pruning on the walnut tree should be completed by mid-November .
Fall is not just the best time to cut. From September to November the ideal time window for planting a walnut tree opens. Inexpensive bare-root goods and young trees with bales grow quickly in the sun-warm garden soil. Add some ripe compost to the planting pit as a natural jump starter for healthy growth.
Build a shapely crown - parenting cut
Tree nurseries and garden centers offer walnut in a version suitable for gardening as a refined young tree on a robust base. “Clone No. 139” is very popular because its later budding is less endangered by late frosts. Refined walnuts bear their first fruits after 5 to 6 years, whereas the real walnut takes up to 30 years until the first flowering period. The upright, richly branched growth of premium varieties as a refinement offers the perfect starting point for training to become a shapely tree, as illustrated below. This is how the educational cut succeeds:
- For the first 4 to 6 years, carry out the parental cut in early autumn
- Build up the crown with a vertical central drive and 3 lateral guide branches
- Select guide branches with different starting points and an angle between 45 ° and 90 ° to the trunk
- Do not cut the tip of the central shoot
The education phase focuses on removing vertical, competing instincts in good time. This applies equally to steep shoots on the main branches and from a base or trunk. Only prune leading branches if they are growing in different lengths. The top buds should be in the juice balance at all times. The top bud of the central shoot is enthroned one or two scissor lengths above the leading branches. Together, the framework forms an angle of 90 ° to 120 ° for an exemplary round crown.
Preferably tie down steep shootsThe walnut differs from apple, pear and cherry in many ways. When it comes to the fertility of shoots, a walnut tree pulls together with pome and stone fruit trees. As long as a shoot grows vertically towards the sky, the law of growth governs peak promotion. At this point, the walnut is not interested in planting flower buds. Before you remove a steep shoot from the crown in a sunny position, you should use its potential to become fruit wood. For this purpose, tie or spread the young, still flexible branch at an angle of about 60 ° to the trunk or guide branch . The growth comes to rest so that flowers and nuts can form.
Cut the tree crown into shape
A well-trained walnut tree rarely requires pruning. The most frequent cause is an undesirable expansion in all directions, which makes a reduction of the crown inevitable. At intervals of 5 to 10 years, a cut-sensitive walnut tolerates the intervention of scissors and saws. With this pattern you can bring a walnut tree back into shape:
- The best time is between the beginning of October and the middle of November when the weather is dry
- Cut off shoots that are at an acute angle to the trunk or main branch
- Remove or tie down the steep shoots sprouting on the main branches
- Cut back excessively long scaffold branches by a maximum of 150 cm
- Streamline massively branched shoot tips through derivation
- Cut branches from 5 cm in diameter to 20 cm long cones
- Step back after each cut to plan how to proceed
A walnut tree will benefit if you are familiar with a derivative pruning. This is applicable if you have a too long geratenen Gerüstast cut or a broom-like branched tip of the branch streamline want. Look for an outward-facing, young side shoot near the intersection. Cut off the used wood at the fork. To avoid injuries to the young shoots, set scissors or a saw a few millimeters into the old wood.
Fruit wood cut pointlessMake a note of a cut on the walnut tree only if the crown has grown too large or shapeless. Cutting fruit wood to increase crop yield is not worth the effort. In contrast to fruit trees with stone or pome fruit, annual pruning measures for the promotion of young fruit wood come to nothing on walnuts. Rather, local conditions and weather determine the quantity and fruit quality of a harvest.
Cut gently on cones
The rare pruning measures on the walnut tree can cause larger cuts. As a rule, the leading branches of a crown are affected, on the upper side of which undesired steep shoots or similar unfavorable branches have to be removed. A cut on Astring harbors the danger that the wound will dry deep into the wood at this point and fatal rot will form. It is more gentle with a cut on tenons. How to do it right:
- Cut off thick shoots from the guide branch or trunk with cones that are 20 to 25 cm long
- Consequence: The cone gradually dries back by half
- After 2 to 3 years, remove dried cone remains in autumn
Using this strategy, dead or damaged scaffold shoots should also be removed from the crown. The particular advantage of the pruning technique is that young shoots grow from a cone base. After a few years, select the most promising, obliquely growing shoot as the new guide branch and remove the rest.
frequently asked Questions
Is a walnut tree self-fertile?
Walnut trees are monoecious and therefore self-fertile. There are female and male flowers on a tree. The male flowers can be identified as hanging, yellowish-green catkins. They appear in April about four weeks before the inconspicuous female inflorescences. Pollination occurs by the wind. A single tree is therefore sufficient for a harvest of crunchy walnuts.
Should a walnut tree be supported with a stake during education? If so, when can the support be removed again?
A support pile performs two important functions. Primarily, it serves a straight growth of the trunk and central shoot. In addition, it prevents wind breakage, which is particularly to be feared on young and thin shoots. Only when a walnut tree has grown well and has formed a thick, stable and stable trunk can the stake be removed. The more wind exposed the location, the longer you should wait.
Is it possible to limit the growth of a real walnut (no processing)? I'm thinking of cutting off the leading tip.
Walnut trees naturally grow quite large. Trees that are not grafted and propagated from seeds can reach heights of 20 meters and more. There is the option of regulating growth right from the start through a parental cut. If you want to keep a real walnut more compact and smaller overall, trim the crown all around. If you only cap the leading tip, it will grow massively in width. The best time is parallel to the fall of autumn leaves between the beginning of October and mid-November. At all other times of the year, a strong flow of sap begins, which significantly impairs wound healing.
Is it possible to keep a real walnut tree in the bucket for a period of 10 years? If so, how big should the pot be and what should you pay particular attention to?
Basically, it is possible to keep walnut trees in buckets. In contrast to the outdoors, a walnut in the pot requires significantly more care. The substrate dries out faster and after a short time has hardly any nutrients to offer. Regular watering and fertilizing is essential. A 20-liter bucket is sufficient to get started, but not for a period of 10 years. The pot should gradually grow to a volume of 200 liters when the tree has reached a height of 6 to 7 meters. To do this, repot the walnut tree every 2 to 3 years.
Two years ago I planted a real walnut that grew from 90 centimeters to almost 200 centimeters in height. Unfortunately, not a single side shoot has formed so far. I actually didn't want the walnut that big. What to do?
Walnut trees naturally struggle with lush branching. Over time, a few side shoots will gradually form. You can speed up the process by cutting the tip of the shoot to 150 or 180 cm. Cut just above a sturdy bud. In this way you create a sap jam on lower-lying buds, which then sprout. There won't be more than two or three side shoots. After all, this number is enough to raise a beautiful crown from it.
The 3 most common mistakes
Without a parenting cut, a walnut tree will grow over your head sooner or later. If a topiary is cut at the wrong time, the splendid tree threatens to bleed out. The same thing happens to a walnut if its branches are not cut on cones. The following overview draws your attention to the three most common cutting errors and provides tried and tested tips for prevention:
|no parental cut||uncontrolled growth, misshapen crown||Raise the crown with a central shoot and 3 leading branches|
|cut in summer or winter||massive sap flow||cut in early autumn|
|thicker shoots are not cut on cones||slow wound healing, spread of wood rot||Cut on cones from a diameter of 5 cm|
The wood quality of walnut trees is on par with precious woods such as mahogany or teak. In addition to the visual advantages, the wood is characterized by a fine-fiber and medium-hard structure. For the care of the cut, these attributes mean a low tendency to splinter and little effort required when cutting. To cut twigs and branches up to 3 cm in diameter, pruning shears with a bypass mechanism are recommended, which leave smooth cuts.