Blackberries: Planting, Growing, and Harvesting Blackberries | The Old ... How to Plant Blackberries For semi-erect cultivars, space plants 5 to 6 feet apart. Space erect cultivars 3 feet apart. Space trailing varieties 5 to 8 feet apart. Space rows about 8 feet apart. Plant shallowly: about one inch deeper than they were grown in the nursery. Growing Recommended Varieties