Corkscrew hazel, Corylus avellana 'Contorta' - care and cutting

The corkscrew hazel, botanically Corylus avellana Contorta, impresses with its spirally twisted branches. In early spring the shrub forms male catkins, which bring the first splash of color into the garden with their golden yellow color. Corylus avellana does not make great demands on the care, but allergy sufferers should better avoid the non-toxic ornamental shrub, as the pollen can trigger hay fever.

Characteristics

• botanical name: Corylus avellana "Contorta"
• Genus: Hazel (Corylus)
• belongs to the birch family (Betulaceae), subfamily hazelnut family (Coryloideae)
• Common name: corkscrew hazel
• perennial
• Height: 3 to 5 meters
• Spread: 2 to 4 meters
• Growth habit: broad and upright with twisted twigs
• Leaves: heart-shaped, fresh to dark green, wavy or curled up
• Flowers: hanging, greenish yellow male catkins, rather inconspicuous female flowers
• edible fruits (hazelnuts)
• Flowering period: from February / March to April
• Origin: England, probably a spontaneous mutation of the common hazel (Corylus avellana)
• hardy
• lime tolerant
• Location: sunny to partially shaded
• Soil type: well-drained, warm
• Soil moisture: slightly moist
• pH value: from 6
• Humus: high humus and nutrient content
• non-toxic
• Plant species: ornamental shrub
• Garden style: solitary in the garden, larger rock gardens

Location

Although the corkscrew hazel was discovered in England around 1900, the heat-loving shrub prefers a location with

• lots of sun OR
• a light penumbra.

Since Corylus avellana Contorta is one of the shallow-rooters, its heart-root system can expand up to four meters horizontally. Therefore, pay attention to the distance to buildings, the neighboring property and cables lying in the ground. The distance to paving stones or curbs should also be chosen generously. The planting distance to other plants and cultures should be a good two meters, as the ornamental shrub has a very expansive habit.

floor

Corylus avellana Contorta grows best in alkaline soils. If the soil is too wet, acidic and compacted, the shrub stops growing. Therefore the pH value should not be below 6. The ideal floor is:

• relaxed
• permeable
• slightly damp
• rich in humus and nutrients

Tip: Since the corkscrew hazel can live up to 100 years, if in doubt, you should perform a soil pH test before planting.

plants

Container goods can be planted all year round on frost-free days. However, the best planting times for container goods are spring or autumn. Before planting, place the plant in water until the root ball is saturated.

• Dig the planting pit
• Size of the planting pit: twice the size of the root ball
• Add excavated compost and horn shavings in a ratio of 3: 1
• possibly Lay a drainage layer made of gravel or potsherds on the bottom of the planting pit (to prevent waterlogging) and cover with soil
• Place the young hazel in the middle of the pit
• fill up with the excavation
• Press the earth down well
• Pour the hazel abundantly

Tip: A bare-root corkscrew hazel should be planted between the beginning of October and mid-November.

Bucket culture

Corkscrew hazel can also be kept in the bucket. The planter should have a volume of at least 30 liters. A pull-out hole at the bottom of the bucket prevents waterlogging. So that the casting or Rainwater can drain off well, you should also create a drainage layer made of gravel and / or pottery shards on the ground. Good compost-based potting soil is ideal as a substrate. The planting itself is carried out in the same way as in garden culture.

care

Once the optimal location for Corylus avellana Contorta has been found, it does not make any great demands on care. If the shrub is satisfied with the care, the location and the soil conditions, it can live up to 100 years. Regular pruning rejuvenates the hazelnut bush and keeps it healthy.

to water

Although the ornamental shrub survives dry periods quite well, it should never dry out completely, otherwise it will stop growing. If there is a longer dry period in summer, you should regularly check the soil moisture. If the soil is too dry, then Corylus avellana Contorta must be well watered. The ornamental shrub, on the other hand, does not tolerate waterlogging.

Tip: In the case of corkscrew hazels in the tub or new plantings, the soil moisture should be checked daily during longer dry periods.

Fertilize

The hazel is best fertilized in the spring before flowering. The ideal fertilizer for the shrub is rich in nutrients, such as compost or an organic fertilizer. After that, you should mulch with compost once or twice a month during the growing season, or fertilize with a small amount of ready-made fertilizer. The end of the fertilizer application is at the end of August / beginning of September, as only fully mature shoots survive the cold season.

Tip: If the hazelnut bush is cultivated in a bucket, it is given a dose of liquid fertilizer every two weeks from March to July.

Transplanting and repotting

If the corkscrew hazel is in the garden, it can be replanted up to an age of five years. The right time is when the ornamental shrub has no leaves, there is no frost and the weather is overcast.

• Cut off roots all around with a spade
• about two thirds of the stature height
• Lift the root ball out of the ground with as much soil as possible
• Place the hazel in the new planting pit
• Fill up with earth and step on it
• water abundantly
• Cut back the above-ground part by the volume of the removed root mass

Tip: Support the shrub with a support stick until it is firmly rooted again.

Repot

In the bucket culture, the ornamental shrub can be repotted regardless of age. The planter should be replaced at the latest when it is completely rooted. When planting in the fresh substrate, make sure that the previous planting depth is maintained.

Cut

If the corkscrew hazel is satisfied with its location and care, it can grow up to 50 centimeters per year. And since it can be up to five meters high and four meters wide, the question of a cut arises for reasons of space. But in order to avoid balding, especially with older plants, you should make an annual cut.

Tip: The corkscrew hazel does not necessarily have to be cut back every year.

Care cut

Even if you have enough space in the garden and the corkscrew hazel can develop freely, you should not do without the annual pruning. This cut includes removing all of them

• dead shoots
• stunted shoots
• damaged shoots

If several shoots cross each other, at least one should be cut out, as they mutually hinder each other's growth. If the shrub has become too compact, you should thin it out so that more light can penetrate into the shrub again. The best time to cut is in early spring, before the shrub begins to sprout.

Tip: Do not cut in frost. Cutting in the blazing sun in February and March is also harmful for the hazel.

Cut back

The corkscrew hazel is mostly cut back for reasons of space. As with the maintenance pruning, early spring is the best time for this pruning. There is no precise indication of how strongly the individual shoots should be cut. Since the shrub is extremely pruning, this is up to you. So it's up to you whether you do

• cut the shoots only slightly, but evenly

or

• subject the shrub to a radical cut, i.e. cut all shoots to within a hand's breadth above the ground.

Tip: The optimal cut is always slightly angled about three to five millimeters above an outward-facing eye.

Cutting wildlings

Wildlings keep sprouting from a refined corkscrew hazel. Since these do not develop a corkscrew-like growth, they must be removed immediately, otherwise the ornamental shrub will lose shape and growth. To prevent this from happening, these shoots are not cut, but torn off at the base.

harvest

The corkscrew hazel does not develop its first fruits until it is ten years old at the earliest. In addition, there must be at least two bushes that bloom at the same time, because the bush is dependent on cross-pollination.

Toxicity

Neither the shrub nor the hazelnuts are poisonous.

Overwinter

An adult corkscrew hazel survives the German winter in the garden without protection. Young plants, on the other hand, need winter protection, especially if they are in exposed locations, they must be protected from strong frost and cold wind. So that the hazel gets through the winter well in the first three years, you should wrap the shrub with raffia mats or a jute sack.

Winter in the bucket

This is different with the bucket culture. The corkscrew hazel definitely needs winter protection here, as there is a risk that the roots in the tub will freeze through. It is best if the hazel can move to a light, frost-free winter quarters. If you have to spend the winter outdoors, for reasons of space, for example, then you should cover the bucket with foil or fleece. In addition, place the plant on a block of wood or a styrofoam plate against the cold from below.

Tip: Since not only the cold of the corkscrew hazel but also drought causes problems in the bucket culture, you should provide the shrub with some water on a frost-free day.

Multiply

Corylus avellana Contorta can be propagated using cuttings and sinkers.

Cuttings

To do this, cut off about 20 centimeters of a shoot and stick in potting soil. To stimulate the formation of roots, put some compost as the bottom layer in the growing container. Until the cutting is strong enough to move, you should keep the soil evenly moist.

Sinker

When propagating with sinkers, you need a little patience until it can be separated from the mother plant. Thereafter

• Drag the selected branch to the ground
• Defoliate places that touch the ground
• make a groove about ten centimeters deep
• Dig in defoliated parts of the branch and weigh them down with stones
• Finally, connect the tip of the lowering device to a wooden stick
• Keep the soil evenly moist

If the sinker is strong enough, it can be separated from the mother plant and planted in its new location. However, depending on the weather and location, this can take several months.

Tip: If it is a refined corkscrew hazel, make sure when choosing the branch that it is not an upright wildling.

Diseases

If the corkscrew hazel is healthy and strong, it is not very susceptible to diseases and pests. Because diseases and pests usually occur when the ornamental shrub is weakened, for example due to an unsuitable location or due to mistakes in care.

Scalyroot (Lathraea squamaria)

Scale root is a parasite that removes water and nutrients from the shrub through the roots. Since this parasitic plant only shows up above ground after ten years, it has firmly embraced the roots of the corkscrew hazel in recent years. In order to get rid of the parasite, the hazel must be dug up so that the scalelot can be removed. Scale root settles in over-fertilized, nutrient-rich soils immediately after the snow has melted.

Hazelnut borer (Curculio nucum)

This weevil specializes in hazelnut bushes. If you notice these beetles on the bush, you should collect them immediately, as the females lay their eggs in the hazelnuts. This is where the voracious larvae develop. You should therefore also look out for small holes in the hazelnuts, this is an indication of the infestation, even if you do not find any beetles (any more). Remove the nuts and destroy them thoroughly (burn them) so that the next generation of hazelnut cutters does not attack your corkscrew hazel.

Bucket culture

In addition to the hazelnut borer, which does not stop at bushes in the bucket, plants in the bucket can also be infested with powdery mildew, spider mites or scale insects.