Ailing Corkscrew Hazel*


I have had a twisted or curly hazel in my garden for about 6 years. Starting last year it began to drop leaves and did not grow much this year. There were few branches with leaves and root stock suddenly began to grow suckers rapidly. The area was not modified in any way and the graft was not covered, it is still about 4″ above the soil. I severely trimmed all the suckers early this spring and took off any dead branches of the original bush that I could determine were actually dead. (brittle)

It is in a semi shady area in a moderately damp area (neighbour’s yard run off beside fence)
Can you recommend anything that will help?


Thank you for contacting the Toronto Master Gardeners concerning your ailing corkscrew hazel – Corylus avellana ‘Contorta’.

Unfortunately there is a possibility that your tree has contracted a lethal disease known as  Eastern filbert blight which is caused by the fungus Anisogramma anomala. Did you happen to  see semi-regular, black cankers along the stems? If your tree is infected with this disease then pruning out the infected wood well below the cankers, before leaf buds break, is about the only way to treat this disease.

The following is from one of our earlier posts:

“In spring, spores are released from mature cankers of infected hazelnut trees and shrubs. Spores are spread by rain and splashing water droplets driven by wind. Young and developing shoots are highly susceptible to new infection. Newly infected shrubs do not show any symptoms for 12-15 months. The second summer following infection, the fungus begins to produce dark-brown to black spore-producing structures called “stroma” within cankers on infected stems. The mature stroma begin releasing spores the following spring. The fungus continues to produce new stroma and releases spores as the canker expands each year. Elongated, sunken cankers, expanding lengthwise on branches will be seen. Cankers are infected areas of sunken, dying tissues formed along a branch. Cankers expand from year to year and girdle the branch, resulting in branch dieback and eventually the shrub will die.

You may be able to prolong the life of your shrub by pruning out any diseased branches with cankers about 2-3 feet below the site of infection. Do not compost the diseased wood. Copper spray is used by nut farmers to control Eastern filbert blight, but it is not one of the allowable cosmetic pesticides for use on ornamental plants.”

Additional information and photos can be found on the following website: Eastern Filbert Blight