Personally I wouldn't do it. I'm a floral designer. Your roses were fertilized in the greenhouses or fields they were grown in. Once they come to the wholesaler and the floral shop, they are often treated with chemicals to prolong their life and bloom. So if you really do love your chams, Don't say it with Flowers.
DO NOT USE THEM. Roses used in floral displays are sprayed with glosses to make them shine and pop for visual appeal. They also sometimes spray fake rose perfume on them to make them more fragrant. I dont know if roses are a good gutload item. I would guess probably not. But the floral roses are a def no-no.