Roses bloomed once this year, and now no buds on plant at all. will the use of moth balls harm them?
If the rosebushes are new plantings, they may be taking a rest period to store up energy for another bloom cycle. Check them over well for any insect damage or insect activity, also check them well for any fungus activity. They may need some treatment if either of such pests are active. Make sure they are well watered and well fed as well. As for the mothballs, I would not use them as they present danger that we really do not need in our gardens or rose beds. Here is a good article on the mothballs issue for you to check out: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/mothballs-in-gardens.htm