Chestnut tree, chestnut – plants, pruning and diseases

The difference between the two chestnuts can already be seen in the appearance of the tree. They are imposing trees, very similar at first glance. The inflorescences are similar, but the leaves are easy to distinguish. The horse chestnut has the typical leaves that are arranged like a hand, large and finger-shaped. Usually there are five, but it can also be up to 11 “fingers”. The leaves of the sweet chestnut are rather elongated, without notches and slightly jagged at the edges. The fruits are similar. They are both in prickly wrappings. The chestnuts are usually a bit larger and longer. In addition, there is always only one chestnut in the shell of the horse chestnut, while the sweet chestnut usually has three.

There are several hundred, rather around 1,000, varieties of sweet chestnuts. They are often adapted to the local climate. Such a tree can live up to 500 years.

There are also different varieties of horse chestnuts, for example the red meat or yellow horse chestnut, the common or Indian horse chestnut, the Ohio or the bush horse chestnut.

Care of the chestnut trees

You have to be aware that both species can grow very large. A height of 20 to 25 meters is normal, but it can also be 35 meters. They are therefore not suitable for the small home garden. But there are also large plots of land. In any case, you need space. In addition, the planting distances to the neighbors must be observed, otherwise there can be trouble.

Trees that are once grown are very easy to care for. You rarely have to water and fertilize little. If you have a nice tree structure right from the start, you don’t have to cut a lot. You can also let the tree grow largely without pruning, just like in nature. However, there are some diseases and pests that threaten the trees.

location

Both chestnuts do not like competition from other trees. Above all, trees that grow beyond their crown are annoying. Climbing plants such as ivy that grow into the crown are also unfavorable. Both trees need light, a lot of light. That is why they are best placed on their own, alone in a wide hallway. Then the diseases can also be better controlled. In avenue trees, for which the horse chestnut is often used, a disease or a pest can spread from tree to tree.

Chestnut

• Likes forest edges, but without competition from other trees.
• The tree needs a warm location, at least six months above 10 ° C. It is therefore ruled out for mountain locations.

Rosskastanie

• Needs a sunny location
• Too little sun inhibits growth and flower formation

Plant substrate

Both trees like a well drained substrate. However, the soil must not be too thin, otherwise the required nutrients will always be quickly flushed out. Both are sensitive to waterlogging.

Chestnut

• Needs a permeable soil that can also store water.
• Fresh, loose and deep soil that has a high potassium and phosphorus content is ideal.
• The tree doesn’t like summer drought any more than waterlogged soil.
• A lime-free substrate is important. It can be slightly acidic.

Rosskastanie

• Moist and well-drained soil, with or without lime, but not acidic
• Lots of clay and sand, well mixed
• A nutrient-rich and deep substrate is important
• Under no circumstances soil compaction

plant

When planting, it is important that the trees get the right substrate. The horse chestnut is completely unproblematic. You can leave a chestnut fruit in a suitable place in the garden over winter. It should have driven out by spring and then take root in the earth. You don’t have to plant it big. Even a specimen grown in a flower pot can be easily planted. You don’t have to pay attention to anything else, just the distance to other plants. This can also work with the sweet chestnut.

But if you have a grafted tree or want to plant a larger specimen, you don’t have to pay much attention. You dig a sufficiently large hole, put the tree in it, pour earth on it again and then form a pouring rim. The roots must be completely swallowed up. This will also eliminate any voids and air holes.

Watering and fertilizing

Older specimens of both species provide themselves with water alone. They have a pronounced root system. Young or newly planted trees need regular water until they are in place.

Chestnut

• Doesn’t like completely parched soil. In the case of prolonged drought, it is advisable to water thoroughly once in between.
• There is no need to fertilize. A little organic fertilizer every now and then doesn’t do any harm.

Rosskastanie

• Water young or freshly planted trees
• Fertilizing is recommended.
• Nitrogen is important for leaf health and growth, phosphorus for flower formation and potassium as protection against various diseases and pests.

cut

When editing, the scholars argue again. Some say the chestnut can be pruned well and abundantly, others warn that the wound does not heal well and is very susceptible to diseases and bacteria that penetrate through it.

It is important to stabilize and maintain the health of the main trunk. But it is also crucial that there is not too much competition from trees all around. If you only cut small branches from the beginning that are no larger than 5 cm in diameter, this is much better than when you later cut thicker branches.

So, educate the tree from the beginning. Then you just have to clear out. This is better for both types. But if you want to cut, here are the instructions:

Crown pruning – stabilization and revitalization of old trees – necessary for the first 10 to 20 years before a strong framework is created

• Cleaning cut – periodic maintenance of the base of the trunk
• Unstable, highly elevated trunk axes must be stabilized by shortening them sharply.
• This also applies to wide side branches.
• Drifting water veins must be removed
• Cut away vertical expulsions
• Shortening of less vital parts of the crown and side branches
• A strong framework remains, everything that is superfluous is cut away
• Of course, cut away dead and damaged branches down to the healthy wood

Cleaning cut – periodic maintenance of the base of the trunk

• Is part of the crown cut
• Performed every two to three years.
• Most important is the maintenance of the trunk base.
• Stick rashes and water veins are to be removed
• It is essential to remove any rashes that have penetrated the surface.

wintering

Horse chestnuts are very hardy. You get along just fine with our Central European climate, even if the winter is particularly cold. However, they are not particularly suitable for mountainous locations. The sweet chestnut has a reputation for needing a lot of warmth. During my research, however, I often read of locations that contradict this. The sweet chestnut is not suitable for high altitudes either, but it is also not as sensitive as is often portrayed. I’ve seen chestnuts myself where I would never have guessed, in areas with very cold winters. So, just try it out. I would pack some young trees. It can’t do any harm.

Multiplication

Most sweet chestnuts need a second tree to reproduce. The planting distance should be at least 10 meters.

Chestnut

• Vegetative by grafting onto a base or by planting a fruit
• Grafted trees are mostly self-fertilizers and bring earlier yields.
• Protect young saplings in winter.

Rosskastanie

• Sow, put chestnuts in water or plant chestnuts
• Sow in autumn or winter – cold germs
• Planting a chestnut is easier
• Soil must be kept slightly moist evenly
• Chestnuts soaked in water will take root after just a few days and can be planted directly at their destination

Diseases

When it comes to the threat of disease, there is hardly any difference between the two chestnuts. Chestnut crab, the threat posed by Phytophthora species, some fungal infections and bark diseases are known and occur again and again.

Chestnut crayfish (KRK infestation) brought in from America, fungal disease, particularly threatens the sweet chestnut

• Spores get into the trees through wounds (cracks in the bark, broken branches, grafting points)
• Can be recognized by the yellowish mycelium on the bark. Sinking or swelling of the tissue
• Cracks in the bark and later withering of parts of the plant above the infested site
• Generously cut back into the healthy wood
• Cutting back weakened branches

Ink sickness , caused by Phytophthora species, mostly affects trees in damp locations. Mycelium penetrates the roots, leads to leaf wilt, a lack of fruit formation and even death of the crown. Black exudates can often be found at the base of the trunk, which incidentally gave the disease its name.

• It is essential to avoid damaging the roots so that fungus cannot penetrate.
• No soil compaction
• Chicken litter can at least partially kill the fungus
• Chestnut mosaic virus – believed to be transmitted by aphids. Often occurs in grafted trees through the grafting point.

Pests

In terms of pests, it is the horse chestnut leaf miner that has become so well known. You can see sick trees everywhere. You can see the brown leaves, which fall off in July / August. The trees are weakened considerably. Severely weakened specimens bloom again in August and September. That robs them of even more strength.

The moth first appeared in Austria in 1989. From there it spreads in Europe, about 100 km further every year. Control in the home garden is difficult because, although there are numerous effective means, they cannot be used. You are not allowed. What remains is to collect the fallen leaves and destroy them. The safest thing to do is to burn the foliage. In addition, the bird population in the garden should be promoted. Free-range chickens are ideal eaters of moths, as are swallows, common swifts and blue tits. If you want to plant a new chestnut, you should choose a scarlet horse chestnut (Aesculus x carnea ‘Briotii’). This variety is largely resistant to the leaf miner and has interesting red flowers.

In the case of the sweet chestnut, it is mainly the chestnut borer and the early and late chestnut moth that threaten the tree and its fruits.

• Chestnut borer – weevil, female lays one egg on each fruit from mid-August, around 40 in total. Larvae eat their way inwards. If the fruit falls off, they eat their way out again and crawl into the ground, where they finally hibernate. Can cause severe fruit damage. The only thing that helps here is to collect the fruit quickly after it has fallen. Destruction of the affected fruits.
• Formerly chestnut moth – butterfly that appears in the evening, at the beginning of summer. Females lay about 180 eggs on the leaves. Caterpillars eat their way into the fruit husks, eat the fruit and then look for a new one. Get from fruit to fruit via silky threads. Pup under the bark. Great damage to the stocks. Combat with light, fruit juice and pheromone traps. Chemical agents are mostly not permitted.
• Later chestnut curlers – similar to earlier chestnut curlers. However, caterpillars overwinter in the ground. Infestation difficult to see. It is usually higher in dry summers and on poor, stony soils. Dispose of infected fruit casings quickly. Control with insecticides if permitted.

Conclusion
Both the horse chestnut and the sweet chestnut are mighty trees. Planting them in the small home garden makes little sense and also little joy, at least after a few years. But if you have space, there are beautiful trees for you. They are easy to care for and also not labor-intensive, apart from leaf fall. However, both types are threatened by some diseases and pests. So you should always keep an eye on them and watch out when changes appear. If you do something about it in good time, you can usually avoid greater damage.