Merriam-Webster Collegiate Dictionary - spirea

 or spiraea  noun  Etymology: New Latin Spiraea, from Latin, a plant, from Greek speiraia  Date: 1669  1. any of a genus (Spiraea) of deciduous shrubs of the rose family with small usually white or pink flowers in dense racemes, corymbs, cymes, or panicles  2. any of several garden plants resembling ~s; especially a shrub (Astilbe japonica) of the saxifrage family