How far apart do you plant Marion berries, and what kind of trellis is required. How many plants does it take for a average family
Clackamas County Oregon
Information about growing these berries can be found in the OSU Extension publication EC 1303, "Growing Blackberries in your home garden". If you paste the URL in your browser you can access the publication, which is free. I would think 3-4 plants would be sufficient for a typical family as the plants are vigorous and quite productive.