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Love fruit? Have you considered planting raspberries in your garden? They take a little site preparation and tending but they can provide a significant source of delicious and healthy berries through the summer and fall. Here’s what you need to know.

Raspberries need:

  • Full sun
  • Good air movement
  • Fertile, well-drained soil
  • pH of 5.5-6.5

Most soils in Pittsburgh that we’ve encountered have a higher pH than this range. To acidify soil, add peat moss or granular Sulfur. Doing a soil test where the raspberries will go is a great way to accurately determine pH, and get recommendations for how to adjust it. (Put in the code for “brambles” when you’re filling out the form.)

Black raspberries at Braddock Farms.

Black raspberries at Braddock Farms.

Planting

Choose plants from a reputable dealer, so they are healthy and disease free from the get-go. Be careful not to let the raspberries’ fine roots dry out; soak the plants in a bucket of water for an hour or two before planting.

To get them started right, add plenty of compost to the planting area. Plan to add more compost, bloodmeal, or soybean meal every spring Plant them an inch or two deeper than where the stem turns to roots, and prune the cane back to ground level.

Water the raspberry plants well. Keep watering very regularly until you see new sprouts, which may show up from the roots rather than from the central cane. Raspberries require 2” of water per week through the growing season.

Spacing

Red raspberry canes sprout from their root system, so they spread. Plan an area that can fill in with the bushes. Ideally, a row of raspberry bushes is 3-4’ across, with plants initially spaced every 28-36.” If you’ve got room for more than one row, the rows should be 8’ apart (due to plants spreading and canes hanging over the walkway).

If you’ve got a less expansive space, black raspberries may be the way to go. They are more contained, since they sprout form a central crown instead of from the roots. You can plant them in the same spacing as red raspberries, or in hills 3-4′ apart.

Raspberries along the fence at Helen Faison edible schoolyard.

Raspberries along the fence at Helen Faison edible schoolyard. Photo by Ryan Sigesmund.

Types

Black raspberries are generally less hardy than red raspberries. But there are several varieties that will thrive in our Pittsburgh Zone 6b. Black raspberries don’t spread like red raspberries, but they do grow lanky canes that need to be cut back in the early summer. They produce a harvest in June/July.

Red raspberries fall into two categories: summer-bearing or everbearing (which is sometimes called “primocane”).

  • Summer-bearing berries produce once a season, within the months June-Aug. Their canes die back after fruiting, and new ones emerge for the next season’s harvest. This type needs a year to establish before producing.
  • Ever-bearing raspberries produce twice in a season. They produce a small harvest in spring, then a larger one in the fall. Spring production is on second-year canes, so during the first year there is only a fall harvest.
Getting ready to trim back some overgrown raspberry plants. Photo by Ryan Sigesmund.

Getting ready to trim back some overgrown raspberry plants. Photo by Ryan Sigesmund.

Pruning

Black raspberries: Trim side branches back to 8-10” in March. Cut back 2-3” of growth in summer when the canes reach 2’ tall. Remove canes that produced fruit, right after the harvest.

Summer-bearing raspberries: After harvest, prune the canes that produced fruit to the ground. Thin the new, first-year canes to every 3-4.” During the growing season, if the canes are bending over to the point of breakage, prune them back to 5.’

Ever-bearing raspberries: For a double crop each season, prune like summer-bearing raspberries. For one late crop, mow or cut back all canes in early spring.

Marking which canes to leave and trimming out the others. Photo by Ryan Sigesmund.

Marking which canes to leave and trimming out the others. Photo by Ryan Sigesmund.

Trellising

Though a trellis is not absolutely necessary, all raspberries can benefit from trellising, as it keeps branches off the ground and fruits from getting dirty.  A wooden post with a crosspiece like a “T,” placed every 15-20’ works well. The crosspiece should be about 2’ across. Run wire cable or twine along the top edge of the T, on both sides of the bed. For black raspberries, the optimal height of the crosspiece (and therefore the support wire) is 40,” while for red raspberries the height should be 36.”