Yellowish Leaves on Spirea --- Help! I have an area of landscaping with Princess Spireas. Plants have been there for several years with lackluster performance. Some have died, been replaced, and died again. The area has partial sun during the day, but I'd say shady 75% of the time. And, I've noticed the leaves on the plants are either yellow, or are a mixture of dark green with yellowish shoots. The plants are close to the foundation of our house, and I give them some Miracle Gro now and then. No obvious sign of pest problems. Elsewhere in the same area Day Lillies and an Althea plant are doing fine. What's my problem? Too much shade? Chemical imbalance?