Lack of water and or spider mites are most likely the problem. Heat and lack of water have taken a heavy toll on shrubs this summer. Due to high water costs some folks have cut back on watering. Evergreen shrubs do not show signs of drought right way as do deciduous shrubs that wilt when they need water. That said, some folks went crazy and watered daily, drowning the poor things. Mulching the beds with a good organic mulch and making sure the soil remains moist all winter is the best bet. Spider mites attack when plants are overly dry or too wet. But they are gone now. When arbs mature they do loose the inner leaves in fall, but if the tips are browning you've got problems. In very late fall I'd fertilize them with an organic slow release ferttilizer such as Holly Tone by Espoma. Happy Yardening, Nancy