Rose petals, rose buds, and rose hips can all be safely fed to roaches as long as the rose bush they come from and the surrounding area aren't treated with pesticides and/or any other harmful chemicals. The rose hips especially, are very high in Vitaman C and other antioxidants and this is the time of year you're going to find them too. I've been harvesting all three lately to feed to my hermit crabs and small animals specifically, but the roaches get their share too. There are also quite a few edible flowers/herbs/plants growing in my backyard (some on purpose, some not lol) that I've been collecting too. Marigold petals (calendula), red clover blossoms and leaves, dandelion flowers, leaves, and roots, and honeysuckle are among the stuff I've been collecting--I've been dehydrating most of it so that I will have a store of it over the winter, and once dried they can be crushed or ground into powder, making it easy to feed small amounts or mix into other foods. I don't have an actual dehydrator, I just set my oven to 200* and depending on the size/density of the different items, it usually takes anywhere from 30 minutes to a few hours, I just check ocassionally to see when they're completely dry. You can do the same thing with fruits, veggies, meats, etc., just slice everything into very thin, small, pieces so they don't take too long.