Plant your Spiraea japonica magic carpet in a full-sun location that receives six to eight hours of sunlight per day and offers well-draining soil. Make sure to choose a planting location that is large enough to accommodate a mature magic carpet shrub; most Spiraea japonica cultivars can grow up to 6 feet tall with an equal spread.
Water your magic carpet regularly for the first three growing seasons to keep its soil evenly moist. Reduce the frequency of watering after the third growing season, once your Spiraea japonica shrub is established. Provide established magic carpet with 1 inch of water per week in the absence of rain.
Fertilize your Spiraea japonica magic carpet shrub in the spring, before new growth is observed. Use a balanced, water-soluble fertilizer like Miracle-Gro, Blooms Plus or Grow More to provide your magic carpet shrub with the nutrients it needs to grow well. Follow the application directions on the fertilizer label when fertilizing your Spiraea japonica.
Pinch faded blossoms off your magic carpet to encourage your shrub to produce additional blooms. Snip the spent blossoms from your shrub with a pair of sharpened and sterilized pruning shears, if preferred.
Prune Spiraea japonica magic carpet shrubs in the early spring to control their size and shape, if desired. Prune away any diseased, damaged or dead branches and foliage to maintain the health and appearance of your shrub. Remove any crossing branches to increase airflow to your Spiraea japonica. Use only sharpened and sterilized pruning tools when pruning plants in your home landscape.