Brambles – raspberries, blackberries and related fruits – are considered a weed in many places. Ohio State University has a section of its “Ohio Perennial and Biennial Weed Guide” dedicated to them.
And while many people love them, if you follow the definition that “a weed as any plant growing where you don’t want it,” the weed definition is appropriate. They can get out of control, even though they are native to the Northeastern United States.
My wife, Nancy, and I have both raspberries and blackberries growing on our property. The raspberries we cultivate, but the blackberries grow wild in a section of the property that we mostly neglect. For a few years after we had the house built in 1975, we also had wild raspberries growing nearby. Those disappeared when a neighbor needed a driveway to their new house.
That introduction is to let you know that if you want to cultivate raspberries and blackberries, you have a good chance of success.
First, a note of caution to those of you who live inland and north of Greater Portland. Raspberries are a Zone 4 plant, which covers almost all of Maine, but blackberries and black raspberries are Zone 5, which is the southern and coastal region. With that exception, the same guidelines mostly apply.
Brambles, the University of Maine Cooperative Extension advises in its Bulletin #2066, prefer a full-sun location with sandy loam that drains well. Don’t plant them where tomatoes, peppers, eggplant and related plants have been grown over the past four years because a root rot called Verticillium could spread to the newly planted canes.
If you don’t have a full-sun location, you can still grow raspberries – it just won’t be ideal, and your berries may be smaller. Ohio State’s brambles-as-weeds article notes that they usually grow at the forest’s edge, meaning that they can take a lot of shade. Our raspberries grow in the shade of a neighbor’s pine trees and have done well for 30 or more years. In short, full sun if you have it, but don’t let the lack of full sun discourage you.
Buy bramble plants locally, so you get hardy varieties that will thrive in Maine’s cooler temperatures and short growing season. I recommend against ever-bearing raspberries because the second crop appears so late it can be damaged by the spotted-wing drosophila, a fruit fly that appears in August. Ever-bearing doesn’t mean you get continuous ripe berries, just a second crop late in the growing season.
Now, for planting. I am writing this column now because this is when raspberries and blackberries are at peak ripeness. You will plant them in early spring, but you can (and should) begin preparing the soil now.
Test the soil. Raspberries prefer a pH of 5.6 to 6.2, so get a soil test and adjust the soil as the university’s soil-testing lab advises.
Get rid of weeds. You can till and plant cover crops (check in next week for instructions on those) or otherwise eliminate weeds, and then add organic matter. We’ve found the neighbor’s pine needles work fairly well as mulch.
Red raspberries spread their roots underground, and are grown as a sort of hedge. The other brambles don’t spread as easily, so they are grown as hills. For that reason, plant red raspberries two feet apart and the others four feet apart. Home gardeners will want just one row because rows should be 8 to 12 feet apart if you grow more than one – too much wasted space for most home gardens.
Brambles are perennials, meaning they can last forever, but the canes grow on a two-year cycle. The first-year canes grow from the ground and produce leaves but no fruit. After the winter, those canes produce side shoots, which will have fruit. New canes will sprout from the ground and provide fruit the following year.
Canes die shortly after producing fruit, and should be cut out either in the fall – which I find easier because I am less busy then – or the following spring.
Raspberries are heavy feeders. The Extension recommends 25 pounds of 10-10-10 fertilizer or the organic equivalent for each 1,000 square feet of the planting site, each year.
In my experience, few people enjoy picking raspberries. It is slow and boring work, and when I pick I am listening either to a baseball game or a recorded book to keep me entertained. Picking can be made easier by supporting the canes. The Extension recommends creating a wire support system that is 3 1/2 feet wide at a height of 3 1/2 feet and tying the canes to the wire. I have the wire, but have yet to find the time to tie the canes to it. The wire keeps the canes mostly upright without tying.
I used old 2-by-4s as wire supports at first but, as I said, brambles last forever and wood supports rot over the years. I now have metal fence supports. And, ever the thrifty Maine recycler, I haven’t used wire but a recycled plastic clothesline.
Raspberries, especially, spread quickly through underground roots. Our raspberry patch once expanded to 20 feet wide making it difficult to pick. We have finally narrowed it to about four feet wide, but regularly pull raspberry sprouts as much as 10 feet from the bed.
Bramble fruit is delicate. If picked in quart containers (strawberry “boxes”), the weight of the berries on top will crush the berries on the bottom. The Extension suggests you don’t pile raspberries more than three berries deep. One advantage of raspberries is that they are very easy to freeze. Eliminate any damaged ones, put the rest into a freezer container and they are good to go.
In an ideal year, you eat the last of the frozen berries just as strawberries are getting ripe the following year.
Tom Atwell has been writing the Maine Gardener column since 2004. He is a freelance writer gardening in Cape Elizabeth and can be contacted at 767-2297 or at:
tomatwell@me.com
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