My guess is that you would prefer to have an evergreen. It is too bad that the Juniperus ashei (Ashe juniper) did not work out. I am wondering when you planted them and if you bought them from a nursery. Ashe junipers do not do well if you try transplanting them from the wild. Nursery stock will do the best and they will also do better if you plant them in the fall when it is cooler so that they have time to establish themselves before they have to deal with extremely hot weather. The other juniper that does well in this area is Juniperus virginiana (Eastern red cedar) and it may be more readily available in nurseries. Both junipers can grow to 30 feet and the Eastern red cedar will sometimes grow higher. Another possibility is Prunus caroliniana (Cherry laurel). It is an attractive tree that can grow to more than 30 feet with shiny dark green leaves. Here are more photos and information for the cherry laurel from OnlinePlantGuide.com. You can visit our National Suppliers Directory to find nurseries that specialize in native plants in your area that have these trees for sale.