According to most sources, trailing berries (i.e. Marion, Logan, Boysen, Cascade) should be planted 6 to 8 feet apart with 8 to 10 plants for a family of 4. For those of us living in cities, this requires too much space. Yet these luscious, soft, juicy, not easy to ship and store berries, are a premium if purchased in the stores. There is always u-pick if you remember to get there before the season ends. And of course, there is always the “wild” Himalaya blackberry, if a new development has not destroyed your favorite picking spot.
My city lot is 65 by 75 feet, with house, garage, deck, sidewalks, patio, all taking space away from plant growing. Yet I have over 50 fruit trees, raspberries, black currents, red currents, grapes, kiwi – you know how it goes when you become involved with raising plants. Lots of plants, too little space. This idea did not originate with me; I first heard it several years ago at the North Willamette Experiment Station, near Wilsonville. I have used it for three years and it is a successful way to raise trailing cane berries. Use the same type of trellis system that all recommend for trailing cane berries. But space the plants four feet apart. I like variety, so I plant a minimum of two each.
Control all the perennial weeds in the area to be planted in trailing can berries. Put in the trellis system at the same time you plant your plants. Plant the plants four feet apart. During the first year, let all the canes grow. Place stakes along the row so that the trailing canes do not grow over your plants. Using the principle of nutrient sinks, you will manipulate the plants to produce more in smaller spaces.
Recall that fruit is a nutrient sink. The plant photosynthesizes feed, which is stored in the stems and roots. When the plants fruits, the nutrients stored are transported to the fruit. The amount of fruit produced is directly related to the amount of food stored by the plant. In the fall, when the canes are trained to the trellis, remove all canes from every other plant. Therefore, you are training plants that are 8 feet apart. Next year, those plants that produced will have all their old canes and new canes removed. Train the plants canes that did not produce fruit. Thus, you rotate between two plants, harvest one year, “rest” the next. During the rest year, the plant is storing more feed than normal, therefore, the following year there will be a increased production by about 50 percent. Give it a try and let me know how you enjoyed so much fruit in so small space.