The birds gave me mine, (or some other critter). I was still in that confused 'what one to buy' when I noted a stick with a few leaves on the path & gave it a chance. (Did not know it was a blackberry either, but always the optimist & would have been happy with a raspberry)!
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Totally thornless, big tasty berries, but a bit huge & thick smooth stems. I couldn't even id that stick as a blackberry! Not answering your question though, but it was over a decade ago, but I have a cutting/stick from it decorating the shed as well, so maybe have a look or chat with the other plot holders as you could get lucky too & not have to pay for a stick or two - (although I think technically they aren't called a stick).
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