Corylus avellana 'Contorta', also known as contorted filbert, is a deciduous woody shrub with an unusual appearance. '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 Great Britain.
Growing to a maximum height of 8 to 10 feet, this deciduous flowering shrub is commonly used in hedge and screen borders where the interesting stems can be observed up close. The cut stems are frequently used in decorative arrangements. Stems can also be grafted onto a host shrub a height of about 4 feet, giving the host a habit more like that of a dwarf tree. This slow-growing shrub is normally planted from balled-and-burlapped specimens or potted plants in fall or spring.
|Botanical Name||Corylus avellana 'Contorta'|
|Common Names||Contorted filbert, corkscrew hazel|
|Plant Type||Deciduous flowering shrub|
|Mature Size||8–10 ft. tall and wide|
|Sun Exposure||Full, partial|
|Soil Type||Loamy, moist, well-drained|
|Soil pH||Neutral to acidic|
|Bloom Time||Early to mid-spring|
|Flower Color||Yellowish-brown catkins on male flowers; female flowers are nondescript|
|Hardiness Zones||4–8 (USDA)|
|Native Area||Asia, Europe|
Contorted Filbert Care
Water quite frequently in the first few years after planting to help the shrub establish a strong root system; you can water less frequently once plants are mature.
Remove root suckers as they appear, since these grow from the rootstock and 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. The catkins are nondescript in winter, but in spring they lengthen to 2 or 3 inches and become yellow. Winter and spring are the best seasons for this shrub. This plant offers no fall-foliage color of note.
Plant contorted filbert shrubs in full sun to part shade.
This shrub prefers well-drained loam rich in organic material and may 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.
Contorted filbert needs about 1 inch of water per week during the growing season. Excessive water can cause the roots to rot, especially in soils that are dense. 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 but may require extra water in very hot climates.
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
Recently, a new cultivar named 'Red Majestic' has been introduced. It has burgundy-colored new growth, which gives the shrub more summer appeal than traditional 'Contorta,' whose foliage is unattractive. 'Red Majestic' also has pink catkins that are somewhat more attractive than the yellow-brown catkins found on 'Contorta.'
Propagating Contorted Filbert
As a grafted plant, contorted filbert is difficult to propagate. Neither the seeds nor the root suckers can be reproduced true to the original plant. Some people have success with soil layering, a somewhat difficult process.
Inspect the shrub monthly for suckers, which should be cut off. Trimming of the bush 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.
This shrub has good resistance to the filbert blight that can devastate other members of the genus.
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 sterile 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 can of soapy water.