How to Grow Blackberry Plants in Michigan

Buy a certified disease-free blackberry bush. Often certified plants are also guaranteed so that if your bush does become sick, the nursery will give you a refund or a new plant.

Dig a hole in a sunny, well-drained location after the last frost in spring. Make it as deep and as wide as the container the bush came in. If you bought a bare-root plant, make the hole about an inch deeper than they grew at the nursery. Slide your plant into the hole and backfill it. For more than one blackberry bush, space them 3 feet apart. If you'll have more than one row, give them 8 feet of separation.

Water the soil around the roots. Blackberry roots are close to the surface and lose moisture quickly. Do not allow the ground to dry up during the growing season, but don't let the roots stand in pooled water, either. In Michigan, plan for your bushes to get 1 inch of water a week either from rain or from your garden hose.

Cut the blackberry bush back. According to the Extension Office at Michigan State University, you should cut your newly planted bush to ground level to prevent disease and fruit from developing right away.

Fertilize your plant. Per each 100 square feet of blackberry row, use 1 to 2 lbs. of 12-12-12 fertilizer, which by weight contains 12 percent nitrogen, 12 percent phosphorus and 12 percent potassium. Feed your blackberry bush for the first time two weeks after planting it. The following year, just before growth begins in early spring, apply more fertilizer around the base of the blackberry plant. Don't let it come in contact with the canes. In the third year, increase the amount of plant food to 5 lbs.

Prune your blackberry canes every two years. Blackberry roots are perennial, but the canes only live two years. The first year, they grow to maturity, and in the second year, they produce fruit and die. In your plant's second year, cut and discard old canes after they bear fruit. Also, prune new canes in early summer down to 18 inches.

Inspect your bush for signs of disease and pests. Michigan blackberries are susceptible to anthracnose, cane and spur blights, orange rust, late leaf rust, botrytis grey mold, powdery mildew, verticillium, insects and viruses. The appropriate treatment will depend on the problem affecting your plant. Contact a nursery or local extension office for help identifying and solving it.