Trim your roses between mid December and mid January, which is the ideal time if you live in Arizona. Not all roses need trimming. If you have shrub roses, floribunda’s, hybrid teas, or grandiflora roses, trim them back to knee height. You may cut off up to ¾ of the bush’s height.
Wait until the blooming cycle has ended and temperatures have dropped below 70 degrees. If you have some bushes that are still blooming after January, hold off from trimming them, but don’t wait any later than February 15.
Cut back once blooming bushes right after they bloom. Generally this is around late spring and the first part of summer. It isn’t necessary to trim back climbing roses.
Do a light trim after September 15. Trim off only approximately ¼ of the rose bush. Slightly angle your cuts approximately ¼ above any bud eyes growing outward. Leave only a few strong stems.