I started a border garden 4 yrs ago with 4 President Grevy lilac bushes which are now 5-6 ft tall, 4 feet wide, and planted about 8 feet apart. They are growing slowly and I would like to add some winter interest with something evergreen and have the important bonus of privacy from neighbors. It is a SW corner location on the lot. There are woods south of the planting area so there is some shade in afternoon, but it does average moderate sun. I've had no luck anywhere in the yard with mountain laurel, so that's not an option. The soil is heavy and rocky, but I will bring in new soil for the new plants. The lilacs get powdery mildew every year but bloom beautifully in spring. Any suggestions for evergreen companions that are fast growing and hardy?