While bone meal is a great organic fertilizer, it will not help with your deer problem. If anything, bone meal may attract some animals, not deter them.
Bone meal has a high concentration of phosphorus in it.
Phosphorus is extremely important to plants. It helps roots to grow and also helps flowering plants to flower. As bone meal is organic, it is slow acting. If you want more flowers next spring and summer put some bone meal around your plants this fall and then again in early spring, about March. While some may find it a little annoying to wait so long to see the benefits of organic fertilizers, such as bone meal, slow fertilizers are usually better for the plants.