Why are my hazel trees producing so few nuts?

Whether you're a gardening beginner or expert, Irish Examiner columnist Peter Dowdall has the answer to your questions

Hazel trees.

Question

I have two cobnut/hazel trees, about five years old, but one, in particular, has been giving very few nuts. 

The shells look good at the start but seem to be affected by a blight that I see around the garden a bit, and either rot or are empty. 

I don't want to spray any chemicals — any other solutions?

Answer

The rotting of the nuts is most probably a fungal infection. 

Good pruning to increase air circulation through the plant will help as will a drench with a solution of copper sulphate and water during April. 

Irish Examiner gardening columnist Peter Dowdall. Picture: John Allen

The problem may be compounded by acorn moth overwintering in the plant. 

As a grub, these can tunnel through the nuts and these holes are in turn infected with fungal or bacterial pathogens. 

An organic winter wash may help to prevent them overwintering in the tree. 

Bats are a natural predator of moths and so if suitable try and encourage bats to the garden.

• Got a gardening question for Peter Dowdall? Email [e-mail]