Blackberry Varieties

Erect and Trailing

• Erect blackberry varieties can grow without support, although many home gardeners provide one or two trellis wires for greater manageability of this bramble-type plant. More cold hardy than the trailing varieties, erect blackberry varieties tolerate climates where temperatures drop to as low as minus 20 degrees Fahrenheit. Rubus "Chester," a semi-erect, thornless cultivar, is one of the most cold tolerant varieties, growing in USDA zones 5 through 8. Rubus "Arapaho" is an erect, thornless varieity grown in USDA zones 6 through 9. Trailing blackberries, called dewberries on the East Coast, require trellising for support. Less cold tolerant than erect blackberries , trailing varieties generally require temperatures no lower than zero degrees Fahrenheit. Rubus "Marion" is a vigorous, thorny trailing blackberry that grows in USDA zones 7 through 9, where it is especially well-adapted to the Pacific Northwest.

Thorny and Thornless

• Blackberry varieties are classified according to whether their canes bear thorns or are thornless. This particular plant characteristic does not affect the flavor, quality or bearing potential of the blackberry, but can be an important consideration for the home gardener for ease of care and manageability factors. Besides the obvious handling features, thornless varieties are less aggressive than thorned types. Rubus "Kiowa," an erect thornless variety, grows in USDA zones 6 through 9 where it produces exceptionally large fruit. Although thornless varieties have many desirable characteristics, thorny blackberries generally produce larger crops. Rubus "Brazos" is a prized cultivar in USDA zones 7 through 9, where it is heat and drought tolerant.

Cane Types

• An extended fruiting season can be achieved by planting more than one variety of blackberry, based upon early-, mid- or late-season ripening. However, the home gardener has another option for having fresh blackberries over a long season by planting primocane-bearing blackberry varieties. Primocanes are current-season growth, which generally do not bear fruit. Instead, most blackberries produce fruit on second-season canes, called floricanes. However, primocane-fruiting varieties were released by the University of Arkansas developers in 2004. Rubus "Prime-Jim" and "Prime-Jan" bear fruit on floricanes during the spring and on primocanes during the fall in USDA zones 4 through 8. Rubus "Prime-Ark 45" is more heat tolerant, where it bears spring and fall fruit in USDA zones 6 through 9.

Winter Chill

• Most blackberry varieties have low winter-chill requirements, needing as few as 200 hours of wintertime temperatures below 45 degrees Fahrenheit. Rubus "Kiowa," hardy in USDA zones 6 through 9, requires only 200 chill hours. Rubus "Black Satin," a thornless, semi-erect blackberry, requires 700 to 800 chill hours where it grows in USDA zones 5 through 8.