Slugs and snails love the flowers as well as several beetles and their larvae. They can leave marks much like teeth marks when they are done munching. Try a little rose dust on the flowers or snail pellets around their bases and see if that helps.
I wouldn't be so sure deer don't get that far. They have been seen at Columns Drive and in North Harbor and it is easy for them to follow creeks and streams up from the river into residential areas.
You can always go out well after dark and see with a flashlight what likes to eat them. I have been plucking slugs off my Angel Trumpets in the early mornings lately.