The corkscrew hazel is a modified variant of the common hazel, the Corylus avellana. Its botanical variety name is Corylus avellana 'Contorta'. In contrast to the corkscrew willow, which shows similar twisted branches, but otherwise has a different habitus, the corkscrew hazel is not a specific breed. Rather, it is a freak of nature. Whether a spontaneous mutation, i.e. a genetic error, or a disease that does not affect the bush any further is responsible - experts do not quite agree on this.
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This wondrous hazel shape was first discovered and described in England around 1900. Impressed by the eye-catching branch structure, people have long since begun to use the shape in a targeted manner through refinement. The common hazel is usually used as a base.
Just like the corkscrew willow, which is sometimes confused with the corkscrew hazel due to the relationship between branch structure and name, the corkscrew hazel is currently enjoying a real boom in gardens. Above all, you not only enjoy the original branch structure directly on the bush, but also like to use individual branches as a purist decoration in the vase.
Origin at a glance:
- Strangely twisted branches either spontaneous mutation or harmless disease
- First discovered and described in England around 1900
- Today targeted “production” of the corkscrew hazel through refinement
- Very popular again at the moment
The basic habitus of the Corylus avellana 'Contorta' does not differ significantly from the common hazel. Like them, it also grows as a multi-stemmed, upright shrub with quite rich, sympodial branching. With rapid growth, the corkscrew hazel can reach 4 to 6 meters in height and around 2 to 4 meters in width. Your crown can become quite expansive and slightly overhanging with age.
Their most characteristic and striking feature are, of course, their corkscrew-like twisted twigs, which are very decorative not only on the bush, but also as pruning. The twisted branches can set a distinctive structural accent in the garden, especially during the winter with no leaves.
The corkscrew hazel can live up to 100 years.
Growth characteristics in brief:
- Like common hazel, upright, multi-stemmed shrub growth
- Fast growth, up to 6 m high and 4 m wide
- Twigs twisted like a corkscrew
- Age up to 100 years
The leaves are also marked by the mutation or disease that gives the corkscrew hazel its name and its special status: because they are not as smooth and straight as those of the common hazel. They show a slightly curled, wrinkled structure and thus take up the motto of the branch.
In terms of size, color and edge structure, however, they do not differ from the leaves of the common hazel: They too have a typically rounded, pointed shape with a double-sawn edge and a light green color. Their texture is finely veined, but looks coarser due to the crimp. The surface is slightly hairy. They start alternately on the branches. Like the common hazel, the leaves turn yellow in autumn and are completely shed towards winter.
Blade properties in brief:
- Are also marked by the mutation or disease and show a frizzy structure
- Size and shape as with common hazel: Roundish, pointed at the front, double-sawn edge
- Light green color, slightly hairy
- Yellow autumn color, leaves shedding completely towards winter
Like its original form, the corkscrew hazel is monoecious - so both male and female flowers are formed on one specimen. The male flowers are already created in autumn and then form the hazel-typical, greenish-yellowish catkins in the end of winter. The female flowers remain enclosed by the bud and have a reddish tip.
In windy weather, the pollen is spread into the surrounding area - for hay fever sufferers, this can lead to severe complaints in February and March. However, bees are all the more happy about the early food source in the year.
Flowers in key words:
- Corkscrew hazel is monoecious with male and female flowers on one specimen
- Male flowers in catkin shape, female flowers budded with reddish tips
- Flowering period from February to March
- Pollen allergenic, but an important source of food for bees in the early year
Hazelnuts have been valued by humans and many animals as a tasty and nutritious natural gift for thousands of years. The corkscrew hazel, like the common hazel, also produces the typical nut fruits from September, albeit to a somewhat lesser extent. In addition, the nuts stay smaller, are not quite as tasty and also not as crispy and tender in consistency, but rather woody.
Therefore, the corkscrew hazel is mainly used as an ornamental shrub. If you would like to harvest a lot of your own hazelnuts, you should rather rely on a common hazel. A corkscrew hazel takes around 10 years to ripen.
Overview of fruits:
- Less productive than common hazel
- Nuts also less tasty
- For good nut yield, it is better to plant common hazel
Which location is suitable?
The corkscrew hazel prefers a sunny to partially shaded place in the garden. The sunnier the location, the more vital it thrives.
What soil does the plant need?
For the corkscrew hazel, the soil should preferably be rich in nutrients and humus, as well as well drained and moist. The pH value should rather be in the high range. In addition, the corkscrew hazel likes it warm on the feet - so it is advantageous if the sun can also penetrate its base and the location is relatively close to other trees or to the house. In general, the corkscrew hazel is quite tolerant when it comes to site conditions.
When planting refined corkscrew hazels, it is important to set the root ball a little deeper into the planting hole so that the refinement point is underground. This will prevent straight wild shoots from growing out, which disturb the appearance of the characteristic winding branches and, above all, quickly overgrow them. You do not need to heed this measure with real-root corkscrew hazels, but such specimens are hardly available.
- Soil for corkscrew hazel as nutrient-rich and humus as possible
- Well drained and moist
- As warm as possible
- pH value rather high
The correct planting distance
The corkscrew hazel still has to be kept a little distance from neighboring plants so that its flat, extensive roots can develop properly. In addition, it looks very good as a solitaire. You should leave a radius of about 2 meters around the bush.
How do I transplant properly?
If possible, you should not transplant a corkscrew hazel. Digging up and moving it to another location means a lot of stress for the shallow-rooted shrub, which should be avoided whenever possible. However, if you want or have to implement it for space or neighborhood reasons, you should only do this with a young specimen. The shrub should not be older than 5 years, otherwise it will have established itself too much in its location.
The best time to transplant is in early spring before the leaves shoot. In addition, there should be no frost.
When transplanting, it is important to dig up the extensive roots generously. This is of course a lot of work, but the less root mass you cut off the corkscrew hazel, the better. The new planting hole should have twice the volume of the root ball and be embedded in a drainage system made of sandy soil. After inserting, fill the hole with humus-rich soil, press it firmly and water it vigorously. A support post for stabilization is recommended.
To compensate for the inevitable loss of roots, you should also prune the shrub back a little.
Pour corkscrew hazel
A corkscrew hazel only needs separate watering when planting and during longer dry periods in summer. Then you should thoroughly water them once.
If you keep them in the bucket, regular watering is of course essential.
Fertilize corkscrew hazel properly
Since the corkscrew hazel needs a lot of nutrients, it is advisable to give it a little extra energy every now and then. In the case of a specimen outdoors, good, ripe compost is best, which you can easily work into your planting substrate in spring.
You should provide a corkscrew hazel in the bucket with a liquid fertilizer about every 2 weeks during the growing season from March to September.
Cut the corkscrew hazel correctly
The corkscrew hazel does not normally need pruning - after all, it is valued for its characteristic growth. It also thrives better and more willing if it is allowed to grow in peace. However, if you should move the shrub in its first few years, pruning is recommended after the transplanting procedure.
Another exception is when wild shoots develop from the planting ground. This happens quite easily, especially with refined specimens. It can also occur in non-root individuals, but it is much rarer. If you notice shoots that are shooting into the shrubbery, this is by no means a harmless aesthetic disruptive factor - because the wild shoots are very vigorous and can quickly overgrow the mutated branch structure.
In this case, you should quickly pick up the scissors to get the characteristic appearance of your corkscrew hazel. Place them as close to the ground as possible on the wild shoots growing out below and be thorough when identifying them.
A radical cutback of old, bald specimens is also possible.
Cutting rules at a glance:
- As such, corkscrew hazel does not need any pruning
- 1st exception: after any transplanting
- 2. Exception: Formation of wild shoots that disturb the characteristic branch pattern and overgrow - cut close to the ground
- Radical pruning possible in old individuals
Propagate corkscrew hazel
Propagating a corkscrew hazel is not entirely trivial because in gardens it is usually a refined specimen. The rooting of grafted parts of plants is therefore a bit difficult. You can still try the cuttings or the sinking method.
From the upper, inner crown of the bush, cut a young, unwooded shoot that has around 4 to 6 leaves. Ideally, you should make the incision directly below one eye. With the exception of the top two, remove all leaves and put the cuttings prepared in this way either in a planter with a peat-sand mixture or in a glass of water. The location should be bright and warm.
The thin, flexible branches of the corkscrew willow that start far below can also be used to lay lowerers. Choose a shoot that is growing on the outside and as young as possible (which should of course not be a wild shoot) and place it in a previously dug notch in the ground. Fix it with a metal hook at the curved intended growth point. Then straighten the shoot tip up and stabilize it with a wooden stick. A wound cut at the attachment point can be helpful.
Besides the harmless disease that gives it its typical appearance, the corkscrew hazel is largely immune to diseases. However, it can be infested with species-specific parasites. Above all, this includes the hazelnut borer, which is also an annoying nuisance for the common hazel. Because it destroys the harvest by laying eggs and developing larvae in the fruits. The nuts will then appear correspondingly perforated.
The weevils are relatively difficult to control. Chemical insecticides against the parasite are not permitted in private gardens. If there is an infestation, you should first collect the adult beetles by hand or shake them off the bush and release them far away from your garden. The infected nuts are also collected and disposed of as thoroughly as possible, preferably burned. So that the hatched larvae cannot survive in the ground over the winter, cover the planting ground with a garden fleece in autumn.
You can also hang a glue ring in the bush as a preventive measure.
If you want to save yourself the frequent removal of wild shoots, when buying a refined corkscrew hazel, if possible, rely on a specimen with the Turkish tree hazel as a base. Such variants are less prone to wild shoot formation than those based on the common hazel. If you would like to get a tall corkscrew hazel, there are also variants refined on tree hazel.
A special cultivated form of the corkscrew hazel is offered in the plant trade, especially in the form of the Corylus avellana 'Red Majestic'.
Corylus avellana 'Red Majestic'
The variant, also known as “red-leaved corkscrew hazel” or “blood corkscrew hazel”, is definitely worth considering as an alternative to the normal Corylus avellana - because, as its common names suggest, it has a very special charm due to its deep, dark red foliage. The male kitten flowers also show a reddish color in this variety. Like the normal corkscrew hazel, the flowering time is in February and March.
In terms of growth, the red-leaved corkscrew hazel is somewhat smaller than the wild species and the green-leaved corkscrew hazel - it is only about 2.50 m high, but due to its bushy branches it is 3 m wide.