Blackberries grow well in California because they adapt to variations in climate. They thrive in extreme heat to moist coastal weather. Blackberries are vigorous growers and need a good watering program. They grow best with the addition of compost to the soil. There are two types of plants, erect and trailing. The erect variety is somewhat self supporting, with long arching canes. Canes of the trailing type require a wire support system. Both types come in thorn and thornless varieties. Berry plants are long lived and require good pruning to produce fruit each year. The berries grow on second-year canes.
How to plant blackberries
Buy certified disease-free berry plants or bare root cuttings from the nursery. Best known trailing varieties are Boysen, Logan, Ollalie and Marion. They ripen mid-June to mid-July. Best known erect types are Black Satin, Cherokee, Cheyenne and Hull Thornless.
Choose a garden spot with full sun and room to create a wire support or trellis. Blackberries need 3 to 4 feet between each plant
Create a wire support structure. Set grape stake poles into the ground, 15 feet apart. Poles should rise 6 feet above ground. Use the screw eye to attach wire between the two poles 2 inches from top.
Repeat this process to attach another wire 3 1/2 feet up from the ground.
Dig holes large enough to accommodate the plant's roots. Spread roots out and cover with soil, packing it down tightly. Water the blackberry plants immediately.
As the berries grow, weave the canes through the trellis system. Do not prune the first year. Blackberries grow on second-year canes. Prune old growth after the first harvest.