How to Grow a Thornless Blackberry Bush

Everything you need to know to care for your thornless blackberry plants.

If you’re wondering how to grow a thornless blackberry bush, you’re certainly not alone. Many blackberry lovers are turning to thornless plants to eliminate the two (literal) pain points of traditional bushes: thorns and invasiveness. Instead, the thornless blackberry bush grows with full delicious berries and an abundance of flowers and foliage.

The key to growing a thornless blackberry bush is to be mindful of the plant’s needs. There are a wide range of climates where thornless blackberries can thrive, but tropical climates are not one of them. The plant will need approximately 250 chill hours for best results.

With respect to planting, thornless blackberry bushes grow best when they have good drainage. This means that tilling the full row where you plan to plant the thornless blackberry is better than digging a hole. Space the plants 8 feet apart in the row and 6 feet apart between rows. Plant your thornless blackberries any time between the last freeze in spring and before the first freeze in fall.

Drip irrigation is the most efficient and consistent way to water and fertilize your thornless blackberry bush. The water in these systems is confined to the root area, which minimizes weeds. Be sure to watch out for critters and cultivate with care, as both run the risk of disrupting the drip system. The plants need 1 inch of water per week. This equates to a half-gallon of water per week. Double this during berry production.

Thornless blackberries grow best when planted in a sunny spot with a minimum of six hours of sunlight per day. You’ll also want to construct a trellis system to help plant maximize its access to sunlight. When constructing the grape-type trellis, use 12-gage wire at the 3- and 6-foot markers, as well as in between. Tie the primary canes along the bottom wire using binder twine or plastic berry clips, the latter of which can be reused for several seasons.

Lastly, in order to protect your thornless blackberry bushes from disease, don’t plant them in soil where potatoes, eggplant, peppers and tomatoes have grown for the previous three years. The soil-borne diseases can live in those spaces for this long. Avoid planting the thornless blackberry bush within 600 feet of wild raspberries or blackberries, as these plants are susceptible to disease and virus transmission that could harm your blackberry bush.