‘Contorta’ is a sport—a naturally occurring variation of Corylus avellana, a shrub commonly known as the common hazel or European filbert. The ‘Contorta’ variation was discovered during the mid-1800s in England. The plant’s common name comes from a well-known Scottish entertainer in the early 20th century who always carried a twisted cane onstage. Growing to a maximum height of eight to ten feet, this shrub is commonly used in hedge and screen borders where the interesting stems can be observed up close. Winter and spring are the best seasons for this shrub. This plant offers no fall-foliage color of note. The twisted stems are frequently used in decorative arrangements, and the shrub is particularly noted for the winter interest it provides in a landscape. During the first few years after planting, water it quite frequently in the absence of rain to help the shrub establish a strong root system; you can water less frequently once the shrub is mature. One of the regular maintenance tasks is the removal of the root suckers as they appear. Because these shrubs grow from the rootstock, they will not have the contorted shape found on the grafted branches. Pruning is normally done to maximize the appearance of the interesting twisty branches; the foliage is bland.
Light
Plant contorted filbert shrubs in full sun to part shade.
Soil
This shrub prefers well-drained loam rich in organic material and can struggle in dense clay soils. It has very good tolerance for alkaline soils. However, if the soil structure or nutrition is not ideal, dig in organic amendments before planting.
Water
Contorted filbert needs about one inch of water per week during the growing season. However, excessive water can cause the roots to rot, especially in heavy dense soils. Frequent watering is more important when the shrubs are young.
Temperature and Humidity
This sturdy hedge shrub tolerates a wide range of temperature and humidity conditions.
Fertilizer
Contorted filbert usually requires no feeding, but if soil tests indicate a deficit, fertilize in late fall or early spring with a granular slow-release balanced fertilizer.
Contorted Filbert Varieties
There are three notable cultivars of Coryllus avellana:
‘Red Majestic’ has burgundy-colored new growth, which gives the shrub more summer appeal than the traditional ‘Contorta’. It has pink catkins that are somewhat more attractive than the yellow-brown catkins found on ‘Contorta.‘‘Red Dragon’ has burgundy-colored catkins, leaf buds, and foliage.‘Rote Zeller’ has leaves that open up as red in the spring and turn bronze-colored over the summer. The catkins are reddish-purple.
Pruning
Inspect the shrub monthly for suckers, which you should remove immediately. Trimming is usually done to enhance the visibility of the contorted, twisty branches as well as to control the size of the shrub. Make each cut about 1/8 inch above a leaf bud, and make sure to make clean cuts without crushing the branches. Be judicious and conservative with trimming, as this is a slow-growing shrub that will require time to recover. To train the plant as a small tree, cut away the lower branches, leaving a central trunk.
Propagating Contorted Filbert
As a grafted plant, usually on the rootstock of the American filbert, C. americana. contorted filbert is difficult to propagate. Neither the seeds nor the root suckers can be reproduced true to the original plant.
Potting and Repotting
Because of its mature width of up to ten feet, as well as the many suckers emerging from the grafted rootstocks, container growing is not a good option for Harry Lauder’s walking stick.
Overwintering
Contorted filbert is hardy to USDA cold hardiness zone 4 and does not need any winter protection.
Common Pests and Plant Diseases
The shrub is highly susceptible to Eastern filbert blight, a fungus that causes branches to die. If not treated, it eventually kills the plant. Occasional disease problems include black knot, crown gall, apple mosaic virus, and leaf spot. Affected branches should be removed and destroyed, but viruses, in particular, are very hard to treat. These problems can be minimized by using sanitized tools when trimming and by keeping the ground around the shrubs free of debris. Leaf spots can be treated with fungicides. Scale insects and Japanese beetles can attack the plant. To control the scale, spray with organic Neem oil at the first sign of their presence. Japanese beetles are easily picked off by hand and drowned in a bucket of soapy water.
Common Problems with Harry Lauder’s Walking Stick
If your shrub gets Eastern filbert blight, it often goes unnoticed because the diseased parts–distorted and swollen branches and cracks in the bark–blend in with the naturally contorted branches. Inspect the shrub carefully if you have other filberts growing nearby that could infect it.
