Share a pic and a weight?
I'm pretty sure you can make some kind of bow out of it, even if very low weight and/or short. I don't know, but I think roses have a fairly low specifc gravity. I do know that they have a fair good sized pith and the bark takes up a lot of space, and they shirk a lot when drying, so that 1 1/4" might be a lot less mass available to take the strain.
This is just a thought that may not be worth anything, but it jumped into my head so I'll share it. A backwards bow, belly nicely toasted and burnished to maximize compressive straigth, with a strong cable backing filling up the pith hole, and sillk under that.