I have aphids on my 2 red rose bushes in Tucson. I have hosed down the plants only to see the shiny leaves reappear.
Aphids on Red Rose Bushes
Aphids can be very persistent. Blasting them off with water continually for a week may or may not give them the message. If they seem to want to hang around, I recommend using a product called Bug Patrol from Planet Natural on-line. That should end the problem and is not such a harsh method either.