Thank you for your reply. I had read somewhere that potting soil could be made by mixing equal parts yard soil, compost, and vermiculite or perlite. I tried this, using vermiculite at first, and using homemade compost. Someone later told me that vermiculite and perlite are not interchangeable in this context, and that vermiculite is too similar to clay, so I should have used perlite. So, for my next attempt, I used perlite instead, and I used a lower percentage of yard soil and a higher percentage of perlite, trying to make my potting soil lighter and faster-draining. It was a little better for the roses than the first attempt, but still not nearly fast-draining enough. My geraniums, hydrangeas, and some other plants seem to do pretty well in it, but not the roses.
The allergic ingredient in commercial soil products that use "forest products" is poison oak, to which I'm very allergic. That's why we make our own compost, to avoid that. But there must be some other ingredient in commercial potting soil that makes it lighter and faster-draining, which I don't have available to use.
I have Sunset's Western Garden Book, but it's been a while since I've read in it. I'll re-read what it says about roses. Thanks