Rose petals have a lot of tannin. I don't know how well they'd work in secondary.
I make 5 gallons of Wild Rose Petal wine every three years and I always add 1/2 tsp of tannin per gallon to the must. For a little bite, along with the flowery sweetness, I will add some sprigs of Dill to some of the bottles. None of it has too much tannin. I never imagined that Rose Petals have a lot of tannin, perhaps Red Rose petals have more than the whitish pink of Wild roses. I usually use 2 quarts of petals per gallon.