The Corkscrew Hazel, known botanically as Corylus avellana ‘Contorta’, is a deciduous shrub celebrated for its dramatic, twisted architecture. Its most captivating feature is the contorted and curling branches, which provide striking interest throughout the year, especially in winter after the foliage has dropped. This unique growth pattern, often referred to as Harry Lauder’s Walking Stick, is the result of a genetic mutation of the common European hazel. Maintaining the plant’s distinctive shape requires routine care.
Establishing the Hazel
For optimal growth, position the Corkscrew Hazel where it can receive full sun to partial shade. Sunnier locations often encourage a more pronounced contortion in the branches. While this shrub is adaptable, it thrives in moist, well-drained soils, tolerating a range of pH levels. Heavy clay soil that retains excessive moisture should be avoided to prevent root issues.
When planting, dig a hole that is approximately twice as wide as the root ball but no deeper, ensuring the shrub is planted at the same depth it was growing in its container. After settling the root ball and backfilling the hole with soil, water the area thoroughly to eliminate any air pockets. A generous initial watering helps establish a strong root system.
Routine Seasonal Care
Consistent soil moisture is beneficial for the Corkscrew Hazel, particularly during the first few growing seasons. Even after establishment, supplementary watering during prolonged dry periods will help prevent stress and maintain healthy foliage. Applying a two-to-three-inch layer of organic mulch around the base of the plant helps retain moisture and regulate soil temperature.
The mulch layer should be kept a few inches away from the trunk to prevent moisture buildup that could lead to rot. While the hazel does not require heavy feeding, a balanced, slow-release fertilizer applied in early spring can support vigor and leaf development. This shrub is quite hardy, generally tolerating temperatures down to around -20°C.
Maintaining the Form
Pruning the Corkscrew Hazel is necessary to enhance its unique ornamental form and prevent its reversion to the straight-stemmed species. The optimal time for this work is in late winter or very early spring, while the plant is dormant. Pruning during dormancy allows for a clear view of the branch structure.
The most important part of this maintenance is the immediate removal of all “reversion” growth, which appears as straight, vigorous shoots. These straight shoots, or suckers, emerge from below the graft union or directly from the roots. These non-contorted branches grow much faster than the desired corkscrew wood and will eventually overtake the plant’s unique shape if left unchecked.
Straight growth must be cut off cleanly and completely, tracing it back to its point of origin on the main trunk or rootstock. If the plant has become congested, thinning the canopy is also beneficial to showcase the twisted branches. This involves removing up to one-third of the oldest or thickest contorted stems each year, cutting them back to a main branch or the ground. Removing inward-growing or crossing branches helps increase air circulation.
Addressing Common Issues
Vigilance regarding the straight, reversionary suckers is a year-round necessity, as they can appear rapidly. Inspect the trunk and the ground around the base of the shrub monthly, removing any straight shoots as soon as they are spotted to prevent them from becoming established.
The Corkscrew Hazel is susceptible to the fungal disease Eastern Filbert Blight (Anisogramma anomala). This blight causes elongated, raised cankers on the branches, which can eventually girdle and kill the infected wood. If cankers are observed, the infected branch must be pruned out immediately, making the cut at least 30 centimeters below any visible sign of the canker to ensure the fungus is fully removed.
Common pests include aphids and scale insects, which can be managed with organic treatments like insecticidal soap or horticultural oil. A proactive approach, combining removal of suckers with an inspection for signs of disease or pest activity during the annual late-winter pruning, will ensure the Corkscrew Hazel remains healthy.