If you want a shrub that is interesting throughout the year, consider planting a contorted filbert. This shrub features twisted branches that are especially attractive in winter when the foliage has fallen. It also blooms early, producing yellow male catkins in late winter and early spring before the leaves arrive. The intriguing twisted branches mean that this plant is best positioned in the landscape where it can be appreciated, such as along the edges of a patio or walkway.
You can expect this shrub to reach a mature height and width of 8 to 10 feet, forming into a rounded shape. The obovate leaves are 2 to 3 inches long and feature double-toothed margins, similar to alder shrubs, to which it is related. The leaves are green for most of the growing season then turn yellow in the fall before falling off. This shrub is monoecious and will have both male catkins and female flowers. The yellow catkins are 2 to 3 inches long; the female flowers are tiny and red.
This variety does not always produce a hazelnut. If it does, the nuts will appear in September and October. Be quick as squirrels may steal the nuts before you have the chance to collect them.
||Corylus avellan 'Contorta'|
||Contorted filbert, Harry Lauder's walking stick, corkscrew hazel|
||8 to 10 feet|
||Full sun to part shade|
||Rich, well-drained soil|
||6.0 to 8.0; alkaline to acidic|
||4 to 8 (USDA)|
||Originally discovered in England as a genetic sport of the species|
How to Grow Contorted Filbert
Contorted filbert will tolerate most soils, but it does not do well in dense clay. A sunny location is best, but the plant will tolerate part shade. Contorted filbert is normally sold balled-and-burlapped or as a potted plant, and it can be planted in either fall or spring. In the first few years, water the shrub frequently to establish the roots. After this, you can reduce watering to once a week or so. Make sure to remove ground suckers as they appear, since these are growing from the rootstock, not the corkscrew grafted branches.
You can plant your contorted filbert in a location that receives either full sun or partial sun, but for fastest growth, look for a full sun location.
The contorted filbert tolerates a wide variety of soils, but it prefers alkaline soil that drains well. It can handle soil textures like sand, loam, chalk, and clay.
Frequent watering is important while the shrub is young (the first year or so), but after this, give it about 1 inch of water per week, through irrigation or rainfall. Too much water can cause root rot.
Temperature and Humidity
Contorted filbert is a very vigorous shrub that tolerates most conditions, but it will appreciate extra water in very hot climates.
Use a balanced granular fertilizer every few months to encourage proper growth for the first few years If this is the first time you are fertilizing after planting, cut the recommended amount in half to avoid burning the shrub. Once it is well established, the shrub may do fine with no feeding whatsoever.
Propagating Contorted Filbert
These shrubs are difficult if not impossible to propagate since the characteristic corkscrew growth habit is achieved through grafting branches onto a rootstock. You may be able to succeed by soil layering the twisted branches.
Varieties of Contorted Filbert
If you would like a shrub with purple leaves, look for the 'Red Majestic' variety of Corylus avellan. It is very similar to 'Contorta' in that it shares the twisted branch habit.
Because 'Contorta' is a grafted plant, you will need to keep any ground suckers in check, as they will not have the characteristic corkscrew branches. Other than this, there is not be much pruning required, except basic maintenance pruning aimed at keeping sidewalks clear of overhanging branches or removing dead, diseased, or damaged branches. You may also want to prune to allow the twisted branches to be more visible, but this should be done conservatively since this is a slow-growing shrub.
Common Pests and Diseases
This sport has good resistance to filbert blight, which is a frequent problem with other varieties of filbert. These shrubs may occasionally be affected by black knot, crown gall, apple mosaic virus, and leaf spot.
Insect pests may include scale and Japanese beetles which can be a serious problem in some areas.
Homeowners in Oregon might want to avoid planting the contorted filbert. The Native Plant Society of Oregon has it listed as an invasive species that has the potential to overtake your yard in the right conditions.