One of my favorite modern California impressionistic paintings depicts suburban gardening of the post agricultural period in the Santa Clara Valley. It is a finger painting that I made in kindergarten at Bucknall School in about 1972 or 3, to illustrate some of my favorite features of my grandparents’ garden in Santa Clara. To the left is a vertical brown stripe below green squiggles with black spots; the avocado tree. To the right is a similar image with red instead of black spots; the cherry tree. Between and below these, and lacking a vertical stripe, is a flurry of green squiggles with more black spots. These are blackberry canes.

            Blackberries are not at all ‘low maintenance’ since they require rather intensive specialized pruning. Most of the work that they need gets done during summer; but bare-root blackberry plants become available and get planted this time of year with other bare-root plants. Blackberries produce fruit on biennial canes which grow during their first year, and then bloom and fruit during their second year before dieing out.

            Once the tough roots are established, there is no shortage of fresh new canes to replace the old canes. In fact, surplus young canes can be dug and divided with roots to propagate new plants during winter. Because they have a way of spreading outward, blackberries should not be planted too near to neighbors’ fences without root barriers to keep them contained.  

            The most popular blackberries locally are ‘trailing’ types such as ‘Boysen’, ‘Marion’ and ‘Olallie’, which are also known as ‘Boysenberry’, ‘Marionberry’ and ‘Olallieberry’.  Less common ‘erect’ types, such as ‘Arapaho’, ‘Chickasaw’, ‘Choctaw’ and ‘Navaho’, are more tolerant to cold winter weather, so are more popular where winters are more severe. Hybrids of trailing and erect blackberries are ‘semierect’, and are generally treated like trailing types.

            After they get planted in winter, trailing and semierect blackberry canes can do whatever they want to through their first year. In their second year, canes should be trained onto trellises or wires until they have finished fruiting in summer. When the fruit is finished, these canes should be cut to the ground.

            Some of the canes that were growing on the ground below the trellises while all this was going on should now be trained like the canes that were just removed. For trailing types, about ten to fifteen of the best canes should be selected, trained and pruned to about six or seven feet long. About half as many canes of semierect types should be selected and pruned about a foot shorter. All remaining canes should be cut to the ground. (A few of the smallest remaining canes may be left intact through summer to be divided for propagation in winter.)     

            Side branches grow from the pruned canes through late summer and early autumn. At the end of the following winter, these side branches should be pruned to about a foot long. New growth from these stems blooms and fruits during the following summer. Again, when fruit is gone, the spent canes get cut to the ground so that the process can be repeated.

            Erect blackberries do not need to be trained onto support. Canes that develop during their first year can be cut to about two and a half feet tall in the middle of summer. Resulting branches should be cut about a foot long in winter. During the following summer, these fruiting canes should be cut to the ground as fruit is depleted. New canes can then be pruned like the previous canes were.