How to Prune & Care for Blackberries

Put a trellis or arbor behind any trailing blackberries for support. Erect blackberries support themselves, but trailing blackberries grow vines and need a structure on which to grow. Tie the woody stems to the trellis with felt ties, and train growing shoots along the wire and wood of the structure.

Water blackberries with 2 inches of water a week and give them a new dose of organic compost every year. Dig up the top 3 inches of soil around the plants and mix 2 inches of organic compost into the site, to increase both drainage and nutrition around the roots.

Feed blackberries in spring, before their spring growth starts, with 10-10-10 or organic fertilizer. This feeding enhances spring growth and blooming.

Don garden gloves and prune blackberries in late winter or early spring before or during this spring feeding, to avoid pruning away anything but old growth. Blackberry canes grow, overwinter, bear fruit and then die, so cut away any vines or branches that had fruit the previous summer. Mark those branches with ties during the summer to track them, then cut them to the ground in winter.

Prune new growth in summer. Cut any newly sprouted canes to 36 inches to encourage them to branch into several shoots. These shoots will all produce fruit the next summer.