Is this to be something free standing or attached to a building or ? If it's to be attached to a wall, why not simply obtain a 6 X 3 and a 3 X 3 and attach one on top of the other on the wall? Or, some other permutation of sizes. You can also cut one (or both) to fit together to make the exact size you want.

I don't know how good a 9 X 3 trellis covered with a large rose is going to look. That's not really wide enough to really espalier it out far enough to encourage foliage and flowers low enough for you to see them, unless you're going to be looking at it from above and aren't concerned with growth and color lower down. Kim

I could probably make it a bit wider. Maybe 4'. It will be freestanding. Wish it could be attached to a wall. That would have been easier.

Ouch! You can't dig holes to sink 4" X 4"s? How sheltered will this "sail" be from strong winds? How about snow? Can you build a structure like a pergola so it has four legs instead of two, for that much more support against weight, wind, etc.? It's going to need to have some weight to it or the mass of the large plant will topple and damage it. That much mass is going to catch a lot of breeze. I don't know what to suggest if you can't anchor it well or provide it structural integrity through a strong frame. I'd be more than a little apprehensive spending any time near enough for it to fall on me. Kim

OK, what about using as thick galvanized pipe for the frame? You should be able to sink it into the ground pretty far (hopefully) or into concrete footings. Manageable length threaded sections might be screwed into galvanized threaded fittings to create both vertical and horizontal strength. You may be able to work in "flying buttresses" into the design to give it more vertical strength and support. On the buttresses, you might grow other climbers or vines.

If holes sufficient for large wooden uprights aren't possible, perhaps appropriately sized holes for strong pipe might work? Kim

I have to agree with Kim. Anything free standing and that tall is going to act like a sail in the wind. It's the same problem I have with my RdV that's on a free standing trellis. With all of the leaf surface of the rose wrapped on the trellis it catches the wind wonderfully and topples it right over and I have to keep standing it back up. It finally broke the metal legs off this spring so now it's got 2, 2x2 stakes front and back on each end holding it up as well. I'd go with something more on the order of a tripod or obelisque if possible. Three or even four legs will make it much more stable. It will also help to hold up the weight of a full grown rose in full bloom. I had one trellis that just collapsed on itself under the weight once. The metal just bent like rubber under the rose. So think strong! There are lots of plans around on line for different kinds of trellises made out of wood, copper pipe, PVC pipe, etc. and you'll have to find some good way to anchor it in the ground deep. With your cold temps anything not sunk deep enough will heave in the winter otherwise.

The one thing I've got going for me is that it is sheltered and south facing so winds are not as much of a problem as they would be otherwise.

Kim - I'm intrigued by your pipe frame idea. Do you have pictures or did you see it somewhere? I was thinking of using concrete to set whatever I decide on.

No, I'm sorry, no photos or plans. I was considering what could be done to create a sufficiently stable trellis for your requirements and the thought of a panel with supports such as "flying buttresses" http://en.wikipedia.org/wiki/Flying_buttress which can be designed out on several levels on which ever sides needed to keep it vertical; "out rigging" http://en.wikipedia.org/wiki/Outrigger like on boats; or "spider legs" as were used by Richard Neutra on many of his modern architecture designs. http://www.waymarking.com/gallery/image.aspx?f=1&guid=2835211c-cf4c-467d-9614-17600e23a4ee They've become so common in so many types of architecture, you're probably seen them used all over. Several can be worked into the total design to provide support to the front and back of the tall panel.

You could also design it like a large, folding screen. The front panel positioned where you need it and the two support sides angled away from the front to provide support, with or without any kind of screening on it upon which to attach plants. Trellis material can be secured to the pipe frames using a number of different methods; wired to it, screwed to it; perhaps eyelet screws tapped into the pipes and wires strung between them like a large kitchen mandolin slicer. Or, actual pipes can be secured in utilizing pipe fittings at the appropriate lengths where you want them. Think large Tinker Toys. Galvanized pipe should be weather resistant enough for the use as well as sufficiently rigid to support the weight of the plant and any snow which collects. I don't know about using PVC. I know it's not terribly weather resistant here due to heat and ultra violet. I have no idea what freezing and thawing might do to it.

I hope it gives you some ideas. It just MAY work! Kim

If you cannot dig holes to set wooden posts, maybe you can use metal posts and pound them into the ground to give your trellis support, just be careful how close you place them to the rose so they don't sever any large roots. I also think having three or four support posts would lend your trellis a lot more strength than just two, maybe you can make an obelisk sort of thing with three posts set in a triangle with wire wrapped around them to train the rose on. I've done that with wooden stakes and twine for temporary vine support and it worked well for me.