Information on Thornless Blackberry Plants for Zones 8 & 9

Trailing Thornless Varieties

• Trailing thornless blackberry varieties have a climbing or trailing growth form and need a strong trellis and regular pruning to control them. Trailing thornless types produce some of the best-tasting fruit available. "Thornless Boysen" was developed in California and grows best in U.S. Department of Agriculture plant hardiness zones 5 through 9. Known for its sweet flavor and abundant juice, this variety ripens in early summer. "Waldo" (Rubus fructicosus "Waldo") grows in USDA zones 7 through 9. This late-ripening variety produces large, sweet fruit.

Upright Thornless Blackberries

• Upright thornless blackberry varieties benefit from a trellis or structure, but can get by without one. These plants produce some of the largest, firmest berries, and are often grown commercially for fresh processing. "Navaho" (Rubus fructicosus "Navaho") was developed at the University of Arkansas and is adapted to USDA zones 6 through 9. It produces large, flavorful fruit in late summer. For an early summer harvest, try "Oachita" (Rubus fructicosus "Oachita"), hardy in USDA zones 5 through 9. This variety produces large, plump berries with a firm texture and tart flavor.

Semi-erect Thornless Blackberries

• Almost all semi-erect blackberries are thornless. These plants grow on slightly arching canes that can reach 12 feet tall or more. The plants have higher yields than other types of blackberries. and are grown commercially for fresh processing. "Triple Crown" (Rubus fructicosus "Triple Crown"), which grows in USDA zones 5 through 9, has a trailing to semi-erect form. It gets high marks for flavor, yields and color. "Doyle" (Rubus fructicosus "Doyle") is adapted to USDA zones 4 through 9. This variety produces large yields of tart berries, ideal for jams and pies.

Planting and Care

• Thornless blackberries need the same care required by thorned varieties. Planted in fall or spring, they thrive in well-drained, rich soil and full sun. Blackberries benefit from an early spring application of 10-10-10 fertilizer, applied at a rate of 1/2 cup per plant. They also need plenty of water, especially when the fruit is developing and ripening. Drought can cause hard, withered fruit. Water thornless blackberries at least weekly for 30 minutes throughout the growing season. Increase watering frequency in dry, hot weather.