Growing and caring for domestic blackberries takes moderate care and attention. This rewarding vine will repay your efforts each summer and fall when the fruits emerge. A healthy blackberry patch produces fruit for 15 to 20 years. Plant domestic blackberries in full sun or partial shade. Blackberry varieties include trailing, rambling plants and erect, upright plants. Some domesticated blackberry species are thornless.
Clear the planting area of all weeds and grasses. Spread a 2-inch thick layer of organic matter over the planting site; seasoned manure, compost or rotted leaves work well. Dig the organic matter into the top 6 inches of soil and smooth out the planting site.
Plant blackberries in the early spring as soon as the ground is soft enough to work. Dig holes that are slightly larger then the root ball of the blackberry plants. Space the planting holes 4 to 10 feet apart in a row for easy trellising.
Slide the blackberry plants out of the nursery pots and place one plant in each hole. The base of the stem should be level with the soil. Fill in the soil and pat it down to secure the plants in the ground. Water the area until the soil is damp all around the roots.
Drive an 8-foot tall wooden or metal fence posts into the ground at either end of the blackberry rows. Sink the 8-foot tall post 2 feet into the ground so that 6 feet is showing above the soil. Run sturdy wire between the two posts at 5 and 3 feet from the soil line. Select a non-rusting garden wire for long-term use.
Fertilize each plant in early spring after the frosts have passed. Apply 1/4 lb. of 10-20-20 fertilizer to the surface soil around each plant. Apply a 1- to 3-inch layer of bark mulch in the late fall to keep the weeds down around the plants.
Apply 1 inch of water per plant each week in one or two watering sessions. During periods of wet, rainy weather discontinue watering. In very hot, windy weather, increase the water amount to 1 1/2 to 2 inches of water per week.
Trim blackberries in the fall after the last harvest. Prune select canes to shape the blackberry plants to the desired shape and size. Or, cut the plant straight across the top to a height of 1 foot. This will stimulate the plant to put out new, vigorous growth in the next growing season.
Harvest the berries by hand when they turn from red to black. Chill the berries immediately after harvesting to preserve their freshness.