Blackberries belong to a family of plants called brambles, which includes raspberries, blackberries, loganberries, boysenberries, youngberries and others. For a backyard patch, recommended varieties include Ebony King, Eldorade, Ranger, and Darrow.
Blackberry plants should be set out in early spring, three feet apart in rows at least eight feet apart. Plant in well fertilized soil full of organic matter. Blackberries can grow in a wide variety of soils and tolerate clay when soil pH is around 6.0 to 6.5. Make sure you plant them in a site where they will get plenty of sunlight to encourage fruiting.
Set the root cuttings horizontally 2 inches below the soil surface. If plants are used, plant them with the root system approximately 2 inches below the soil line. Do not fertilize at this time; wait until a drenching rain settles the soil. To create a hedgerow of blackberries, plant cuttings or plants 2 to 4 feet apart in the row. If you want to keep the plants separated, plant them 8 feet apart in the row.
Cut canes to 12-16 inches at planting. A trellis will help keep the long, branched stalks from becoming tangled and making the patch impassable.
Plants need water to produce big berries. When possible, install plants near a water source in case irrigation is needed. When watering, apply enough water to wet the soil at least 8 to 10 inches below the ground surface, but do not plant berry plants in low areas where water stands after a heavy rain. Blackberries under these conditions would have a tough time growing.
If properly cared for, 15 plants will supply enough berries for an average family.
Fertilize blackberries twice a year. Apply about 2 ounces of 10-10-10 premium-grade fertilizer containing micronutrients to trailing blackberries in early spring and midsummer of the first year. Scatter the fertilizer evenly over a circle 2 feet in diameter centered on the plant. Erect blackberries are usually planted closer together, so apply 1 pound of 10-10-10 fertilizer per 18 feet of row in the spring and 1 pound per 36 feet of row in summer.
In subsequent years, apply 1 pound of 10-10-10 fertilizer per 9 feet of row in late winter and 1 pound of 10-10-10 fertilizer per 18 feet of row in early summer. Spread the fertilizer evenly over the row in a band 2 feet wide.
Brambles are biennials, growing on a two-year cycle sending out shoots the first year and berries the second. Do not prune the first year’s growth; after the second year, cut back the new canes to about 30 inches to encourage branching. Mulch around the plants with organic material about three inches thick.
Blackberries ripen during the hottest weeks of summer, so give them frequent heavy watering at that time. Water several times each week after the fruit has set and starts to ripen.
Blackberries are ripe and at their peak flavor when they lose their high-glossy shine and turn slightly dull. The best time to harvest berries is in the late morning hours after the dew has dried. This is generally when the berries are at their juiciest.
Depending on the weather, picking season begins by midsummer. It can be expanded by planting a variety of cultivars with different harvest times.
Blackberries are self-fruitful and will continue to grow indefinitely as long as they are care for and cultivated.