I don't think that is something that is easy to achieve, due to the fact that the rose command pieces a lot of things together to generate the eventual figure.
If you want to rotate the figures to include them in a presentation or something like that, a workaround could be to rotate all the text in Matlab, then export to eps or png or whatever you're going to use, and then rotate the graphic file before you insert it into your document (in latex, the graphicx package lets you rotate pictures easily). For example:
texthandles = findall(gca,'Type','Text');
Now you can export and then rotate by 90 degrees, the 0-degree axis will be on the top.
Alternatively, maybe the FEX has something for you.