Little vampires suck all the sap and rasp their tender skin. Like fleas, but worse. Poor plants! Squish them and spray them off with the hose. Plant alyssum and other small nectar producing flowers to feed ladybugs and lacewings. Once you have an army of good guys, you won't see many aphids unless ants are protecting them.

Roses self protect against aphids.

Title: DYNAMIC ASPECTS OF THE CHEMICAL RELATION BETWEEN THE ROSE APHID MACROSIPHUM-ROSAE AND ROSE BUDS
Author: MILES P W

Author affiliation: WAITE AGRIC. RES. INST., UNIV. ADELAIDE, ADELAIDE, S. AUST.

Published in: Entomologia Experimentalis et Applicata, volumn 37, pages 129-136, (1985).

Abstract: "Dynamic aspects of the chemical relation between the rose aphid [Macrosiphum rosae] and rose buds.In warm weather, M. rosae (L.) walks off buds of hybrid tea roses during a critical period coinciding with the opening of the sepals. This behavior could not be related to histologically detectable barriers to feeding, nor to changes in the water content of the tissues or in their composition with respect to total soluble carbohydrate, amino nitrogen or phenolic compounds; major changes in tissue chemistry, effected by spraying the bushes with urea, did not affect the time at which the aphids left the buds. Tissue sap expressed from stems and sepals showed a significant increase in catechin content after, rather than during, the critical period. Once expressed, however, sap from buds at the critical stage showed a sharp in vitro rise in catechin content over a few hours, up to levels approximating those against which the insects discriminated in choice tests. The insects could well be sensitive to a developing capacity of tissue to accumulated catechin, possibly in response to their feeding activity."

Aphids spread at least one rose virus: https://sites.google.com/site/rosespringdwarf/home

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"The high incidence of RSDaV in glasshouse samples is unsurprising as the virus is known to be transmitted by the rose-grass aphid (Metapolophium dirhodum) and the yellow-rose aphid (Rhodobium porosum) (Salem et al. 2008a). The rose-grass aphid has been present in New Zealand since early 1980’s (Allen and Lee 2006) and has also been observed to heavily infest rose glasshouse crops for cut flowers (E. Milleza, unpublished data). "

The above is from one of the few modern rose virus research papers available free in complete form (not just the abstract):

https://www.researchgate.net/profile/J_Tang/publication/257801675_A_survey_of_viruses_infecting_Rosa_spp_in_New_Zealand/links/54c6a7760cf238bb7d093f40/A-survey-of-viruses-infecting-Rosa-spp-in-New-Zealand.pdf