The canes should be planted in an area where no herbicides have been used for two years. The rapid growth of the nursery matured canes will be susceptible to almost all herbicide residues in the soil. Be sure to know the history of your site. It is always best to have at least one year of site preparation before planting valuable horticultural crops. The best time to plant berries is in early spring. Blackberries are best started from root cuttings. These plants should be planted into well prepared weed free soils. New plantings must be kept weed free and well watered. DO NOT use any herbicides until plants are well established, this usually means late in the fall after they have been growing for an entire season or the following spring.
The tops of the new plants may die back or not grow at all.; This is common and not a problem as new shoots will emerge from the roots. DO NOT REMOVE OR REPLANT THE PLANTS THAT DIE BACK. If you think the plants have died dig down to check the roots for life or just wait. All of the plants will grow if cared for properly.
Blackberry is easily grown in a good well-drained loamy soil in sun or semi-shade. Plants have biennial stems; they produce a number of new stems from the perennial rootstock each year, these stems fruit in their second year and then die. Blackberry canes are long and can be very thorny depending upon variety, growing in groups or thickets. Canes branch and can grow up to 15 feet or more in length and thickets can extend to hundreds of square acres in an area. Canes die off after 2 to 3 years but are usually retained in the thickets making them largely impenetrable. Leaves are light green, serrate and palmate with 3 to 5 leaflets or fingers, the main vein on the back of each leaflet has thorns. The flowers are white, five petaled and bloom in April and May. Fruit is usually ripe in late June through July. Gather edible fruit when ripe, can be frozen or canned for later use. As soon as the last fruit has been picked in summer, cut all the old canes and burn them. Be careful not to cut out the new canes in the process as they represent next year’s crop. The new canes should be tip pruned from June to September to form a bushy hedge.
Train semi trailing blackberries to trellises.; Construct the blackberry trellis by stretching a wire between posts set 20 ft apart in the row.
Generally, only a small crop of fruit is produced in the first season. If growth is poor during this first season, cut the canes back to several inches in late winter to force development of sturdier, more fruitful canes. In the second and succeeding years, shoot growth is more vigorous and upright. Tie these new shoots to the trellis when they reach a length of 4 to 6 ft.
Some growers prefer to wait until harvest is over and old canes have been removed before tying new shoots to the wires. Pruning the old canes is critical to the prevention of disease. After harvest, prune damaged or weak canes, leaving 4 to 8 new shoots. Tie these canes to the trellis in a fan shape (do not bunch them). In the spring before growth starts, prune any laterals back to 12 inches to encourage larger fruit.