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Growing Blackberries in Washington

By James Young ; Updated September 21, 2017

Though not native to the Pacific Northwest, naturalized wild blackberries grow on waste patches of land throughout the region. Gardeners in Washington spend more effort removing and controlling the Himalayan blackberry than growing this bramble fruit. Improved varieties offer the Washington gardener larger fruit size, higher yields and even thornless harvests.

Growing Blackberries

Till the berry bed a year in advance if possible. Early tilling helps control weed growth and allows amendment of soil. Work in plenty of rotted organic matter. Growing a cover crop such as annual ryegrass and tilling it under increases soil tilth. Test the soil and choose fertilizer accordingly. Till in half the recommended amount of fertilizer before planting. Save the rest to use as side dressing when spring growth begins.

Plant blackberry varieties known to do well in your part of Washington. Local growing conditions vary widely from western to eastern parts of the state. Seattle blackberry varieties may not survive winters east of the Cascades. Dewberries produce well west of the mountains but more than one variety is required for pollination. Self-pollinating Cherokee blackberry matches well to conditions in eastern Washington.

Dig planting holes 4 inches deep in the center of the new bed. Plant in late winter. Keep canes vertical. The different varieties of blackberries grown in Washington require different spacings--use the distance appropriate to the cultivar. Vigorous trailing dewberries need about twice the space as cultivars with upright canes. Typical spacing ranges from 4-8 feet. Leave 10 feet between rows.

Set posts 15 feet apart in the row if growing trailing varieties. Drive support stakes into the ground at the end of the row. Angle the supports at 45 degrees away from the trellis. String two support wires--the top wire at 5 feet and the bottom wire at 3 1/2 feet. In Washington, erect varieties that are correctly pruned don't need trellising.

Train new trailing canes by wrapping the canes loosely around both wires in a spiral. Tie the canes to the wires with wire ties. If growing erect cane blackberries, select three or four of the strongest canes from each plant and prune the rest back to the ground in midsummer. Tip-prune the remaining canes to 3 feet in height.

 

Things You Will Need

  • Tiller
  • Hoe
  • Rake
  • Blackberry plants
  • Fertilizer
  • Fence posts
  • Sledgehammer
  • 12-gauge electric fence wire
  • Wire clips
  • Support stakes
  • Pliers
  • Pruning shears
  • Wire ties

Tips

  • Blackberries fruit on second year canes. After the harvest cut out the old canes and leave new growth to replace them.
  • For trailing varieties, leave new canes on the ground below the trellis until after harvest. Clip out the old canes and clear the trellis completely before training the new canes to the wires.

Warning

  • Varieties recommended for Washington may need winter protection east of the mountains. Choose cold hardy types and provide a windbreak if possible.

About the Author

 

James Young began writing in 1969 as a military journalist combat correspondent in Vietnam. Young's articles have been published in "Tai Chi Magazine," "Seattle Post-Intelligencer," Sonar 4 ezine, "Stars & Stripes" and "Fine Woodworking." He has worked as a foundryman, woodturner, electronics technician, herb farmer and woodcarver. Young graduated from North Seattle Community College with an associate degree in applied science and electronic technology.