sounds like you have a problem with too much heat or sun or possibly a soil that is too alkaline. Some rhodendrons tolerate more sun than others. Azaleas tolerate more sun generally than rhodendrons. Boxwoods can be kept low for many years, same is true with some of the hollies that provide color in all seasons. There are numerous dwarf conifers as well. Many people here plant Alberta spruce here because it grows slow and is pyramidal. From what little I know of landscape design, I avoid the pyramidal plants on the corner of the house because they make the house seem smaller, but to each his own. There are also dwarf crepe myrtles that never get very tall at least here where I live if you love color like I do and aren`t particular as to heat, dry conditions or soil. The problem besides hardiness here is Japanese Beetles with them the last 5 years. I wouldn`t recommend anything that Japanese beetle cherish