Fertilize this spirea in late winter, right before it comes out of dormancy. Use a fertilizer for flowering shrubs and follow directions on the package regarding the amount and application method.
Give Magic Carpet Spirea at least 1 inch of water weekly. During hot weather spirea may require more frequent watering. Check the soil twice weekly during hot weather -- use a spoon, a stick or your finger to dig 1 inch down. When soil is dry at that level, water again.
Spread a layer of straw or other organic mulch loosely around the spirea 3 to 4 inches deep. This helps keep the soil moist, as well as offer extra warmth to roots in the winter.
Prune your spirea to shape it after it finishes flowering in the spring. Cut back dead branches at this time as well.