The best characteristics of a dozen species of native Rubus species are represented in modern blackberry varieties. Dependable and easy to grow in Zones 6 to 9, several new primocane blackberries (which bear on new canes in late summer) produce good crops in Zone 5. Among the most nutritious food crops you can grow, blackberry plants begin bearing a year after planting, and continue to produce for many years with minimal care.
Types of Blackberries
Erect blackberries can be grown as a head-high hedge that needs little or no support when properly pruned. Good erect blackberry varieties include ‘Navaho’ (which are thornless) and numerous varieties with thorns, including ‘Illini Hardy’ and ‘Darrow.’
Semi-trailing blackberries need a fence or trellis to keep them upright, but with good pruning these thornless varieties can produce very high yields. Good varieties include ‘Chester,’ ‘Doyle,’ ‘Natchez’ and ‘Triple Crown.’
Trailing blackberries grow long, wandering canes that need guidance and pruning, like climbing roses. At their best in the cool Northwest, the ‘Marionberry’ cultivar has thorns, but ‘Waldo’ and ‘Loch Ness’ are thornless.
Primocane blackberries bear on the current season’s growth, starting in midsummer. Varieties such as ‘Prime Jim’ and ‘Prime Jan’ (both thorny) can extend the blackberry season into early fall, or make blackberry production possible where cold winters cause cane injury in other blackberry varieties.
How to Plant Blackberries
Growing blackberries is easy in a sunny to partially shaded spot that has well-drained soil with a pH between 6.0 and 6.5. Enrich the site with plenty of organic matter so that the top 6 inches of soil will retain moisture well. In garden-size plantings, allow 4 feet between erect and semi-trailing blackberry plants, or 6 to 8 feet between trailing varieties. Single plants of very productive varieties such as ‘Triple Crown’ can be grown on an upright pillar, or you can plant two or three plants together in a mound. Plant crowns about 3 inches deep, and water well.
For recommended planting dates for your local climate — and to design your garden beds — try our Vegetable Garden Planner.
Mulch blackberries with 3 inches of an organic mulch year round. Chopped leaves, grass clippings, wood chips and sawdust are all good blackberry mulches. In spring, feed established plants with a balanced organic fertilizer or a topdressing of composted manure before renewing the mulch.
In midsummer, cut off the tops of new canes at no more than 6 feet from the ground. This pruning triggers the growth of heavy-bearing lateral branches. In fall or early spring, prune the tips of these lateral branches to 12 to 18 inches long. Pruning is especially important with productive varieties such as ‘Nachez’ and ‘Triple Crown,’ which tend to set huge crops of small fruit when left unpruned.
Harvesting and Storage
Blackberries are ready to harvest about 40 days after blooming, but most varieties taste best when allowed to ripen to dull black before they are picked. Harvest ripe berries in the morning when they are cool, and handle them carefully to avoid crushing. Refrigerate immediately. Whole washed blackberries, patted dry, can be frozen for later use. Blackberry juice, jams and jellies are easy to process in a water bath or steam canner.
In spring, as soon as new green sprouts appear, use a sharp knife or small spade to cut shoots with roots attached from parent plants. Transplant immediately. Most blackberries also can be propagated using the tip layering method, in which the tips of long canes are encouraged to bend over and take root in nearby spots.
For growing advice for many more garden crops, check out our complete Crops at a Glance Guide.
Contributing editor Barbara Pleasant gardens in southwest Virginia, where she grows vegetables, herbs, fruits, flowers and a few lucky chickens. Contact Barbara by visiting her website or finding her on Google+.