If you want a plant that is interesting throughout the year, consider planting a contorted filbert. This shrub features twisted branches that are especially apparent in winter. It also blooms early, producing yellow male catkins in late winter and early spring before the leaves arrive.
Those in Oregon might want to reconsider planting the contorted filbert. The Native Plant Society of Oregon has it listed as an invasive species, so this has the potential to overtake your yard in the right conditions.
The name on record for this shrub is Corylus avellana 'Contorta' and it is under the Betulaceae (birch) family. Other related genera include alder trees (Alnus spp.), birch trees, hazel trees and shrubs (Corylus spp.), hop-hornbeam trees (Ostrya spp.) and hornbeam trees (Carpinus spp.).
Contorted filbert, corkscrew hazel, contorted European filbert, and European hazel are names you may commonly see for this shrub. It may also be called Harry Lauder's walking stick after the entertainer from Scotland since he sometimes used a twisted walking stick made from this shrub.
The appropriate USDA zones for the contorted filbert are 4 through 8. Corylus avellana comes from Europe and western Asia. The 'Contorta' variety comes from a shrub found in England. Plant your contorted filbert in a location that receives either full sun or partial sun. Try to find a place with full sun for optimal growth.
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" long and feature double-toothed margins. They are green for most of the growing season and 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" long. The female flowers are tiny and red.
This variety does not always produce a hazelnut. If it does, they will appear in September and October. Squirrels may steal the nuts before you have the chance to collect them.
Design and Growing Tips
This is a great choice for a specimen plant. It certainly draws the eye with its interesting curved branches and yellow catkins. If you would like a shrub with purple leaves, look for the 'Red Majestic' variety. It is very similar to 'Contorta' in that it shares the twisted branch habit.
The contorted filbert prefers alkaline soil that drains well. It can handle soil textures like sand, loam, chalk, and clay. Since this is a cultivated variety of Corylus avellana, it is propagated through grafting and layering.
Maintenance and Pruning
Use an acidic fertilizer every 1.5 months to encourage proper growth. If this is the first time you are fertilizing after planting, cut the recommended amount in half to avoid burning the shrub.
You will need to keep any suckers in check as they are coming from a rootstock that is different than the 'Contorta' variety and will not have the characteristic corkscrew branches. There will not be much pruning required otherwise unless it's maintenance like clearing parts away from a sidewalk or removing branches that are dead, diseased or damaged.
Pests and Diseases
Some pests that may attack include:
- Bark beetles
- Gall mites
- Japanese beetles (Popillia japonica)
- Crown galls
- Eastern filbert blight
- Leaf spot
- Leaf and twig blights
- Powdery mildew
- Root rots