Good question and I am interested in the replies from those with more experience. I don't think there is really a right or wrong answer here...but, I have chosen not to tip my trailing TC blackberry primocanes during the growing season. This is mainly due to living in zone 5 where you are almost guaranteed to have winter die back. In the spring, I tip them back removing the die back. I am afraid if I tip them during the growing season, I may have more winter die back to remove and end up with less fruiting canes the following summer. I'm fairly new to this though.

The Wild Treasure plant on right is very vigorous. After a number of wraps it was tipped. That multiplied the number of tips several fold which required more tipping.

The plant in the back left, variety unknown maybe Obsidian, but moderate vigor didn't require tipping.

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Black Diamond on the other hand is a compact dwarf and thornless. So easy to work with in a small space. No tipping needed in my system. It still has a fair/good yield and fruit as good as any other I grew. Really not sure how yield compares to others. Probably not quite as good as some. I really just want a few berries for variety. And the fruit, to me, is way better than most blackberries.

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This shows the potted growing system better. Don't think Black Diamond is in this picture. Wild Treasure is second from right. It has thin, long, vigorous canes requiring many warps or tipping. Pots about 3 gal actual volume. Train by running one shoot up each stake, down the other side, and around to form a wreath.

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This post was edited by fruitnut on Wed, Jan 15, 14 at 10:42

Thanks.