TC are very vigorous as you are finding out. How far apart are they? Have you topped them yet? Keeping them down to five feet will require vigilant pruning, but not that much more than keeping them at 6-8 feet as alot of people do. Most people on this forum recommend topping the canes at some height, maybe 6 feet. I have mine on 8-foot trellises using 10-foot 4x4 posts buried two feet in the ground. I'm new at this so I can't tell you how it will work out.

I've got some doug fir posts i need to bury and then run some line across. Mine are about 5ft but they are just taking off like nuts. They are also flowering right now.

I top my Chester's at about 8' which is the height at which I can comfortably reach. I plan to do the same with my new Triple Crowns planted this year.
-Glenn

The triple crown canes should be topped at 6 or 7 feet. By this time they should be showing evidence of making side branches lower down. A support system cross-beam could be as low as 5 or 6 feet above the ground; tying the main cane to the cross beam at this height is plenty of support for the main cane, assuming the laterals are also tied to the support system eventually. Any portion of main protocane and laterals above this height are plenty sturdy and will not collapse under their own weight. A support system much taller than this is for people who like to climb ladders.

I was thinking of asking this same question. Most information I've found is directed toward trellising trailing blackberries, but I've read in brief asides (in Bowling's book and Reich's book) that you can top them shorter than you would for trellising (at 5' or so) and tie them to a sturdy post (mound system?) with some loss in productivity, but a gain in landscaping usage.

Larry, I was hoping to get away with using 6' T-posts, but was unsure of whether the fully loaded plants would be too much for the posts in a strong wind (I think one of my books recommends a 4-6" diameter cedar post). Your crossbeam sounds like a good idea. I was also considering putting closer to 2' of the T-post underground.

Do all black berries need to be trellised? I've got some chesters and some kiowa's and they are no where near needing a trellis. The chesters are still only 4 inches tall at the highest and the kiowa's are maybe a foot tall. I just planted them this year though, plus it's been raining for the past 3 weeks.

Thanks. Didn't know I needed to top em out. Will get to work.

Should black raspberries be topped like blackberries? One of my books said to do that so I did last fall with my one black raspberry plant. It sent out around 3 side laterals right below the topped spot but has not fruited on the side laterals at all. The main cane has a good 100 black raspberries on it now though.

I have a blackberry trellace (2 wires between steel posts) and the top wire is about 5" high. I top all my canes about 6" to 1" higher and tie them to the wire. I get tons of side shoots and lots and lots of berries. I have triple Crown, Kiowa, and ouachita plus a couple other kinds I've forgotten the names of. For Black Raspberries I use the same type trellace with the wire about 3" tall and top my canes just above the wire. Works great for me. Berries taller than 6' are a pain to pick for me.
RED

You wouldn't have to trellis or support caneberries if you have room to let them sprawl and want to practice yoga movements to pick them all. Below is a system using steel field stakes, 2x2 cedar top connectors, vinyl-coated clothesline, and 1/2" PVC pipe. This keeps the berry patch confined to an 8x10-foot area. The cross-bars are 5 feet off the ground. Yes, you have to remember to duck.

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Note below the vinyl-coated line and PVC pipe one foot off the ground for drip irrigation.
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Below is a typical tie-off of a main cane using macrame; it is easy to unknot and reuse year after year.
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And even with this setup, I will be using a 2-step ladder!

Nice setup Larry_gene! Thanks for sharing the pics!
-Glenn

Larry, great pics. Thanks for posting those. I like the fact that the trellis is easily assembled from readily available parts. I may try a similar design on my trellised berries.

Any guess as to whether one of your T-posts alone could support one triple crown plant (i.e., one freestanding post for each plant)?

dj,

The main advantage to my design is no hole digging and no external guying is needed for stability. Good for the small garden, might not scale up for long-term, heavy production.
This particular setup is 12 years old.

If you could get the longest field stakes and drive them into fairly solid soil, that is, solid a foot down and deeper, a single stake should support a clump of blackberries. But then what do you do with the laterals?
Also, the canes around a single stake may not be symmetrical and create an imbalance, causing the single stake to lean over time.

The cedar top-connectors keep all stake tops in a permanent alignment. You might have success, though, using this setup for individual rows, instead of top-connecting in both directions; that is, just have a free-standing row instead of a grid. I didn't think my soil was solid enough to try it.

And the drip irrigation is optional; a square-pattern sprinkler is just as effective placed in the center of the patch. The sprinkler spray stays below nearly all of the fruit.

Black raspberries growing along the length of an un-topped cane:
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I have topped blackcap canes in the past, but you really need a vigorous main cane for the resulting laterals to be productive.