Chester Thornless Blackberry
Rubus fruitcosus 'Chester'
To extend the harvest, plant Chester, which starts its late season, huge production right when Triple Crown leaves off. Very large, flavorful berries start ripening in August and an extremely heavy yield continues all the way until frost. Very similar to Triple Crown, fruit is borne on vigorous, thornless canes.
Unusually versatile and resistant to cane blight, plants do well in both cooler and warmer summer areas, where berries stay firm in the heat. Cold hardy to USDA Zone 5.