Raspberry renewal

My raspberries are at least twenty years old - I still had good yeilds, except last year and more noticably this year, which was down drastically. So despite, garden compost,
deep watering, 20-20-20 etc its likely time to replace. Our garden is full of tall trees, but the raspberry patch, about 20' long, has sunshine till about 4pm these days.

Whats recommended for the North Shore? And is this a good time to replant, or should it lie dormant for a year, or?

Many thanks, experts! Ellis

 

Check this out. Note Disease and Insect Problems section.

You might want to try the 'Chilliwack'.

http://cru.cahe.wsu.edu/CEPublications/eb1640/eb1640.html#raspberries