After tasting and reading about the various thornless and/or upright growing blackberries, I was very happy to give them a try. After building an inadequate structure from T-posts and electric fence wire, I finally took a look thru GardenWeb and found out how to do it better. I built two 24' trellises. I have yet to add the horizontal support wires. Here's #1:

I used 10' long 4-by-4's sunk 2 feet into the ground. I think using 10 footers like this is the way to go. I doubt that I will later regret that the trellis is too high. The three sections are 8' wide. I should have done two 12' sections but I decided to lengthen the trellis after having built two sections, so I just added a third. Instead of the recommended 'T' formation along the top, I just used a single 2-by-4. With only an 8-foot span, I think that's adequate. I'll also likely be using 12-gauge wire instead of the recommended 9-gauge. Again, the wire will be supported at 8-foot intervals which is considerably less stress than a 16-foot span for example. And 12-gauge wire is pretty darn stout stuff.

After building trellis #1 and learning a few things, I built trellis #2:

This one has two 12-foot spans with a 'T' formation at the top to keep the posts from tipping towards each other from the strain of the (soon to come) wires. Instead of bolting them to the posts, I just supported them with brackets and sandwiched them between the posts. Seems reasonable. I will use 9-gauge wire on this trellis, although the thought of working with that stuff seems daunting.

The wires will pass thru holes drilled thru each post and anchored at each end-post with a wirevise. A wirevise anchors the wire, and allows it to slide thru the wirevise in one direction only. This allows you to tighten up any slack that may develop. They're very reasonably priced, assuming they work and last a long time. Here's a link that tells about them.


Wirevise


I think I'll run three wires on each trellis spaced two feet apart. Maybe only two wires spaced 3 feet apart where I'm using the 9-gauge wire.

I'm planning to put Triple Crown on trellis #2 and Kiowa on trellis #1. Yes, I know, Kiowa has major thorns but I'll live with them. I'm thinking 4 Triple Crown on one trellis and 6 Kiowa on the other, giving 6' and 4' for each plant respectively. Is this reasonable spacing? Should I spread them more? Can I spread them less?

I'll post my results with the Wirevises after installation. I think if they work well alot of folks here could make good use of them.