The corkscrew hazel develops a bizarre appearance that creates a romantic and mystical atmosphere. This form probably originated from a disease that has been shown to be harmless. It has been preserved to this day through targeted breeding and does not only delight garden owners with its aesthetics. The corkscrew hazel does not make high demands on maintenance and is considered adaptable and robust.
Characteristics
- known under the name 'Contorta'
- Special form of the hazel (Corylus avellana)
- Birch family (Betulaceae)
- first discovered in England around 1900
- reaches heights of growth of up to six meters
- bizarre appearance due to twisted branches
- Crown spreading broadly with drooping branches
- Flowering period: February to April
- Harvest time of the fruits: August to September
Location and substrate
The corkscrew hazel is adaptable and feels comfortable in places with sunny to partially shaded and warm conditions. It also thrives in shady locations, but where it shows reduced growth. The substrate should be well-drained, because on compacted soil that is prone to waterlogging, the shrub persists in growth depressions. A fresh, moist to moderately dry and nutrient-rich soil offers ideal growth conditions. The corkscrew hazel prefers a pH of 7.0. Acid substrates should be improved with a structurally stable and high-quality potting soil.
Tip: Plant the shrub as a specimen tree. A location surrounded by air ensures that leaves that are wet with rain can dry off quickly.
to water
The need for water decreases with age. Well-grown trees have a higher tolerance to dry phases than young plants. In the year of planting out, you should water the shrub regularly. Before each casting unit, test whether the top substrate layer has dried well. Water the plant thoroughly and thoroughly. Excess water should run off well, because corkscrew hazels do not tolerate them
Fertilize
Trees outdoors are fertilized every two to four weeks from the beginning of March. Mature compost or horn shavings are ideal. You can stimulate growth in spring by administering a compound fertilizer and working it into the soil. Continue the nutrient supply with an organic fertilizer until August. Then switch to a potassium fertilizer or comfrey liquid manure so that the shrub can optimally prepare for winter. The fertilization will be completely stopped from September. This is how you take care of corkscrew hazels in pot culture:
- Use liquid fertilizer
- every two weeks between March and July
- then reduce fertilization
- Stop fertilizing from August or September
Cut
Before every cut, the tool should be cleaned thoroughly to prevent pathogens from collecting in the cut. Make sure the cutting blades are sharp. Bruises unnecessarily injure the shoots. The cut surfaces should be as sloping as possible.
time
The ideal time for pruning is the period of low vegetation between October and March. During this time the shrub is in the dormant phase. Since the leaves are missing, the flow of sap in the branches is interrupted and pruning measures are easier to carry out. Choose an overcast and frost-free day. Intense sunlight can dry out the cuts and damage the shrub.
Note: A regular cut is not necessary. Bare branches and diseased twigs should still be removed regularly to prevent the crown from being thinned out.
Radical cut
Corkscrew hazels are easy to cut and can also be radically cut back to the desired size. This is mainly necessary for old trees that are badly out of shape or have grown too tall. In old age, corkscrew hazels tend to shed. You can counteract this development with a radical cut. When shortening, make sure that
three to four eyes remain on the branch. The shrub sprouts in these places in the coming growing season.Thin out
So that the crown grows tightly and remains aesthetic, you should remove the oldest branches every now and then. Cut two to four branches at the base to make room for fresh spiral shoots. Shoots that have grown too long are shortened by two thirds. If two branches cross, one of them should be removed. Branches that grow into the crown or that rise steeply are also cut off at the base.
Cut refined variants
If the corkscrew hazel has been refined as a base on the common hazel, you must regularly remove the so-called wild shoots. They shoot out of the base of the trunk and grow upright. If the shoots are not cut off, the overall appearance of the corkscrew hazel is disturbed. Wild shoots should be separated in spring:
- cap with secateurs
- cut with a spade
- Injuries to the trunk are quickly regenerated
Multiply
Corkscrew hazels are vigorous and can be propagated without any problems. Both cuttings and sinkers can be used for this.
Cuttings
Unwooded shoots are ideal for propagating cuttings. These grow inside the crown and should have at least four to six leaves. They are pruned in the fall so they can take root over the winter. The chance of successful rooting is particularly high if you cut off the shoot below one eye. Remove all but the top pair of leaves and perform the following steps:
- Make a peat-sand mixture
- Fill the pot
- Sink the cuttings two-thirds into the substrate
- Place the vessel in a warm window seat
- Keep the substrate constantly moist
Tip: Cover the bottom of the pot with a layer of compost and then fill the pot with a nutrient-poor substrate. This promotes root development.
Sinker
Bushy shrubs can be propagated with the help of flexible shoots. Pull a branch on the outside of the shrub towards the ground and remove the foliage from where it touches the ground. The leaves should be retained at the tip of the shoot so that the shoot can continue to grow. The following measures are necessary for successful root formation:
- Dig a channel 10 cm deep
- Bury the leafless area and weigh it down with stones
- Tie the tip of the shoot to a wooden stick with a string
- Keep the substrate moist
Depending on the weather and location, it can take several months for the sinker to develop roots. When this is strong enough, it is separated from the mother plant and planted in the desired location.
plants
Corkscrew hazels are offered as container goods and can be planted all year round. On frosty winter days you should plant them in the garden
- Thoroughly water the root ball
- Dig a planting pit with twice the volume of the root ball
- Observe a planting distance of 200 cm
- Insert the bush
- Mix the excavated material with compost or horn shavings and fill it into the hole
Press the soil well and water the shrub. For an effective use of the water, you can design a pouring rim. This drops towards the base of the trunk and ensures that irrigation and rainwater do not run off the surface.
Repot
Corkscrew hazels prove to be the ideal growth for the bucket. Every two to three years, the shrub is repotted in a larger planter, which is filled with high-quality compost-based potting soil. The minimum volume should be 30 liters. Excess water must be able to escape through a drainage hole so that the roots do not stand wet. Use a clay pot so that the water balance in the substrate can be optimally regulated.
Tip: Always pay attention to a balance between foliage and roots. If necessary, you can cut back branches or roots.
Overwinter
Well-ingrown specimens are hardy and do not require any special protection from frost. Young plants are sensitive to cold air and ground frost. In the first three years, the trees should be provided with winter protection. Wrap the shrub with raffia mats or put a burlap sack over the branches. Grafted shrubs are protected at the base by piled leaves. A layer of mulch made of brushwood and straw protects the tree grate. Container plants must also be protected from frost when they are old, as the substrate in the pot freezes quickly:
- Place the bucket on a wooden block
- wrap with foil or jute
- Water on frost-free days
- ideally overwinter in a frost-free place
Diseases and pests
Healthy plants prove to be robust against pests and diseases. Neglected care or suboptimal site conditions weaken the shrubs, so that problems can occasionally arise.
Hazelnut borer - Curculio nucum
This weevil specializes in hazelnut plants. Females lay their eggs in hazelnut bushes so that the newly hatched larvae can feed on the nuts. Pick up beetles and remove infested fruits. To prevent the spread of pests, the nuts should be burned.
Scalyroot - Lathraea squamaria
This parasitic plant settles in over-fertilized soils and removes nutrients and water from the wood. It has a development period of about ten years, which it spends exclusively in the substrate. During this time it wraps around the roots of the host plant. If you discover the plant in the trunk area, you must expose the root ball and remove the parasitic plant and its roots.
