A ‘Black Satin’ thornless blackberry bush grows on wires supported by 3-foot-long pieces of rebar drilled into the posts on a low wall. Lavender flowers cover the vine for most of May, and blackberries produce from late June through mid-August. The author grows many edibles in her northern California yard, but few give such delight as this one plant. It stretches 12 to 15 feet, and bears at least 8 quarts of berries every summer. You can let your dinner guests harvest their own berries. In fall, the leaves are a vibrant yellow.