Blackberries, black raspberries, red raspberries and yellow raspberries are all very closely related. Botanists separate the raspberries from the blackberries by determining if the core stays in the ripe fruit or if the core is lost during picking. Berries with the core intact are blackberries and berries that lose the core and resemble a thimble, are raspberries. A few berries are a cross between the two. The Loganberry keeps its core intact and is classified as a blackberry. Tayberry has a core that sometimes sticks to the fruit and sometimes comes free of the fruit – especially if over-ripe. Both the Loganberry and Tayberry are crosses between a blackberry and a raspberry. Due to growth habit, they are classified as trailing blackberries. Among the trailing blackberries, we include many well-known varieties such as Boysenberry and Marionberry.
Though closely related there are several quite different growth habits found among the blackberry-raspberry family. All bear fruit on two-year-old wood, or in the case of the everbearing raspberries, they also fruit on the first year growth. Everbearing raspberries are more accurately called Primo Cane Fruiters-as they are not truly everbearing. They have also been frequently called two crop raspberries because they bear a late summer of fall crop on the first year growth (primo canes) and a second crop the following spring on the two-year-old wood. It may help clear up a lot of confusion about blackberry and raspberry culture if one remembers that after flowering and fruiting, any cane that bore fruit does back to the crown.
When establishing a new planting-whether a raspberry planting or a blackberry planting-it is very important to cut the top back on the bare-root transplants, if this has not already been done at the nursery or garden center. All the new growth that will arise from the transplant will come from primary buds just below the soil line. If one examines the crown of the plant, you will see 2.5 small buds or shoots just above the roots at the base of the crown. All top growth above the primary buds is cane that grew in the nursery row the previous summer and is now two-years old and programmed to flower and fruit. If one leaves this two-year-old top growth intact it will start blooming and try to fruit at the expense of the new cane growth that one is trying to encourage from the primary buds. Without a properly established root system, the newly transplanted blackberry or raspberry can even end up dying in an attempt to ripen fruit on the excess cane. By cutting the tops back on your raspberry or blackberry transplants, a much better survival rate can be expected and better growth will result.
Any plant being transplanted to a new site in the garden is going to undergo some stress. By cutting back your blackberry or raspberry transplant, much of the stress is relieved. It takes 4-6 weeks for new growth to start showing so we normally leave 3-5 inches of the old top above ground to “mark the plant” in the row. In summary, it pays to purchase your plants from a professional nursery that will ensure you are buying quality plant material. After bringing the new blackberry or raspberry plants home soak the roots in water for an hour or so prior to planting. One can plant the root system intact, but if the planting hole is smaller than the root system of the transplant, prune the roots to flit rather than “wad” them in the planting hole. Because the plant is dormant and no leaves are present to transpire moisture, avoid over watering. Over watering can only lead to root, rot. Normally spring soil moisture is adequate to guarantee growth if the root system was soaked prior to planting. After growth starts and leaves appear some irrigation will be necessary in the same quantities one would use to establish a rose garden. Fertilizer requirements for raspberries and blackberries are the same as for roses. Caution-do not use rose fertilizers that contain pesticides in addition to the fertilizer, as these pesticides may not be approved for use on berries. Future “Cultural Tips for the Successful Grower” will expand on the similarities between rose and berry culture.