Posted: 12/04/2015 at 19:14
Many roses that have deep red or purplish flowers have reddish leaves and stems too, particularly on new growth - the pigment is in the whole plant, not just the petals.
Etoile d'Hollande is just one I can think of with deep red flowers and similar stems and leaves.
Think of a beetroot - the leaves have red stems and veins and often the leaves are purplish too.
Roses with white and yellow blooms tend to have pale green leaves. Same reason.