I was discussing planting raspberries and blackberries together recently on a visit to the Bay Area. I had always been taught that planting these two types of berries near each other could be detrimental to the health of both due to disease spread. A family member, who is a very good gardener, said he has great success with both these berries close together in his edible landscape. He figured the long-held concept of keeping them apart was a myth, so I thought I would research it.
After looking at university horticulture sites, reading blogs and advice from nurseries, I found out he is correct. These plants can work quite well in the same area, with a few precautions. They have similar growing requirements: full sun, well-drained soil and slightly acid to neutral soil pH. They each take about three years from planting to reach maturity and both remain productive for eight to 12 years.
Although diseases can spread between these two types of brambles, it is no more likely to occur than from one raspberry plant to another. One way to avoid diseases in the first place is to buy disease-free nursery stock (certified virus-free if possible), rather than to plant root or stem cuttings from your own or a neighbor’s existing bramble bed. Additionally, avoid planting raspberries or blackberries near peppers, tomatoes, potatoes, eggplants (all members of the Nightshade family), other small fruits or where these crops have been grown in last five years due to potential for Verticillium Wilt disease transference.
The main reason to keep raspberries and blackberries separate is that their growth patterns are different. Raspberries can be more erect and may or may not need trellising depending on the cultivar. Blackberries usually trail with long sweeping canes and should be confined to trellises, although there are erect blackberry cultivars available.
Summer-bearing raspberries and blackberries have first-year canes (primocanes) on which only leaves grow. They do not produce flowers or fruit until the second-year canes (floricanes) develop. These second-year canes then die to be followed by more primocanes followed by more floricanes and so on. Fall-bearing red and yellow raspberries do produce fruit on their primocanes. Fruit develops in late summer and early fall, after which the tops die out. However, the canes are not dead. Buds appear on the lower part of these canes in spring, producing berries again in the summer.
For an excellent publication on growing and pruning brambles, see University of Idaho, http://www.cals.uidaho.edu/edcomm/pdf/bul/bul0812.pdf.
JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at firstname.lastname@example.org.