Trim blueberry bushes in late winter before new growth shows. Removing unnecessary branches at that time helps the plant direct its energy into producing a better crop of berries.
If a blueberry plant is less than three years old, only remove branches that are damaged or rub against each other. In older plants, trim obliquely growing stems by cutting them off at the main cane. Pruning dormant buds stimulates the plant to grow larger berries on fewer canes. Do not prune a blueberry bush in the fall because it stimulates new growth during warm periods; freezing winter weather would kill the tender new shoots.