If you visit the Library of Organic Information
and the Guides you'll find lots of specialized programs that deal with roses.
Here is the Roses Organic Program
. Roses grew and thrived long before the chemical companies came along and suggested different means. You can compete against toxic chemicals, and your yard will be a much happier space.l Another tip not listed there, I hear people talk about getting used coffee grounds (from places like Starbucks) and sprinkling them under the roses they'll be very happy.